#include<bits/stdc++.h>
#define N 1e6+10
using namespace std;
namespace Octane {
	// non terrae plus ultra
#define OCTANE
#define BUFFER_SIZE 100000
#define ll long long 
#define db double
#define ldb long double
	char ibuf[BUFFER_SIZE], obuf[BUFFER_SIZE];
	char *p1 = ibuf, *p2 = ibuf, *p3 = obuf;
#ifdef ONLINE_JUDGE
#define getchar() ((p1==p2)and(p2=(p1=ibuf)+fread(ibuf,1,BUFFER_SIZE,stdin),p1==p2)?(EOF):(*p1++))
#define putchar(x) ((p3==obuf+BUFFER_SIZE)&&(fwrite(obuf,p3-obuf,1,stdout),p3=obuf),*p3++=x)
#endif // fread in OJ, getchar in local
	
#define isdigit(ch) (ch>47&&ch<58)
#define isspace(ch) (ch<33&&ch!=EOF)
	
	const ll pow10[] = {
		(ll)1e0,  (ll)1e1,  (ll)1e2,  (ll)1e3,  (ll)1e4,  (ll)1e5, 
		(ll)1e6,  (ll)1e7,  (ll)1e8,  (ll)1e9,  (ll)1e10, (ll)1e11,
		(ll)1e12, (ll)1e13, (ll)1e14, (ll)1e15, (ll)1e16, (ll)1e17, (ll)1e18,
	};
	
	struct Octane_t {
		~Octane_t() {
			fwrite(obuf, p3-obuf, 1, stdout);
		}
		bool flag = false;
		operator bool() {
			return flag;
		}
	}io;
	
	template<typename T> inline T read() {
		T s = 0; int w = 1; char ch;
		while(ch=getchar(), !isdigit(ch)&&(ch!=EOF))
			if(ch == '-') w = -1;
		if(ch == EOF) return 0;
		while(isdigit(ch))
			s = s*10+ch-48, ch=getchar();
		if(ch == '.') {
			ll flt = 0; int cnt = 0;
			while(ch=getchar(), isdigit(ch))
				if(cnt < 18) flt=flt*10+ch-48, cnt++;
			s += (db)flt/pow10[cnt];
		}
		return s *= w;
	}
	template<typename T> inline bool read(T &s) {
		s = 0; int w = 1; char ch;
		while(ch=getchar(), !isdigit(ch)&&(ch!=EOF))
			if(ch == '-') w = -1;
		if(ch == EOF) return false;
		while(isdigit(ch))
			s = s*10+ch-48, ch=getchar();
		if(ch == '.') {
			ll flt = 0; int cnt = 0;
			while(ch=getchar(), isdigit(ch))
				if(cnt < 18) flt=flt*10+ch-48, cnt++;
			s += (db)flt/pow10[cnt];
		}
		return s *= w, true;
	}
	inline bool read(char &s) {
		while(s = getchar(), isspace(s));
		return s != EOF;
	}
	inline bool read(char *s) {
		char ch;
		while(ch=getchar(), isspace(ch));
		if(ch == EOF) return false;
		while(!isspace(ch))
			*s++ = ch, ch=getchar();
		*s = '\000';
		return true;
	} 
	template<typename T> void print(T x) {
		static int t[20]; int top = 0;
		if(x < 0) putchar('-'), x = -x;
		do { t[++top] = x%10; x /= 10; } while(x);
		while(top) putchar(t[top--]+48);
	}
	struct empty_type{}; int pcs = 8;
	empty_type setpcs(int cnt) {
		return pcs = cnt, empty_type();
	}
	inline void print(empty_type x){}
	inline void print(double x) {
		if(x < 0) putchar('-'), x = -x;
		x += 5.0 / pow10[pcs+1];
		print((ll)(x)); x -= (ll)(x);
		if(pcs != 0) putchar('.');
		for(int i = 1; i <= pcs; i++)
			x *= 10, putchar((int)x+'0'), x -= (int)x;
	}
	inline void print(float x) {
		if(x < 0) putchar('-'), x = -x;
		x += 5.0 / pow10[pcs+1];
		print((ll)(x)); x -= (ll)(x);
		if(pcs != 0) putchar('.');
		for(int i = 1; i <= pcs; i++)
			x *= 10, putchar((int)x+'0'), x -= (int)x;
	}
	inline void print(char x) {
		putchar(x);
	}
	inline void print(char *x) {
		for(int i = 0; x[i]; i++)
			putchar(x[i]);
	}
	inline void print(const char *x) {
		for(int i = 0; x[i]; i++)
			putchar(x[i]);
	}
	
	// support for string
#ifdef _GLIBCXX_STRING
	inline bool read(std::string& s) {
		s = ""; char ch;
		while(ch=getchar(), isspace(ch));
		if(ch == EOF) return false;
		while(!isspace(ch))
			s += ch, ch = getchar();
		return true;
	}
	inline void print(std::string x) {
		for(string::iterator i = x.begin(); i != x.end(); i++)
			putchar(*i);
	}
	inline bool getline(Octane_t &io, string s) {
		s = ""; char ch = getchar();
		if(ch == EOF) return false;
		while(ch != '\n' and ch != EOF)
			s += ch, ch = getchar();
		return true;
	}
#endif 
	
	// support for initializer_list
#if __cplusplus >= 201103L 
	template<typename T, typename... T1>
	inline int read(T& a, T1& ...other) {
		return read(a)+read(other...);
	}
	template<typename T, typename... T1>
	inline void print(T a, T1... other) {
		print(a); print(other...);
	}
#endif 
	
	//  give up iostream
	template<typename T>
	Octane_t& operator >> (Octane_t &io, T &b) {
		return io.flag=read(b), io;
	}
	Octane_t& operator >> (Octane_t &io, char *b) {
		return io.flag=read(b), io;
	}
	template<typename T>
	Octane_t& operator << (Octane_t &io, T b) {
		return print(b), io;
	}
	
#define cout io
#define cin io
#define endl '\n'
#undef ll
#undef db
#undef ldb
#undef BUFFER_SIZE
}
using namespace Octane;
const int M=5000100;
int e_num,krscal[1000100],head[2*M],to[2*M],nxt[2*M],val[2*M],st[2*M][22];
int n,m,b[100100];
struct edge{
	int u,v,w;
}arr[100100];
bool cmp(edge x,edge y){
	return x.w>y.w;
}
int find(int x){
	if(x==b[x]) return x;
	else return b[x]=find(b[x]);
}
void addd(int x,int y){
	b[find(x)]=b[find(y)];
}
int krscalfind(int x){
	if(krscal[x]==x) return krscal[x];
	else return krscal[x]=find(krscal[x]);
}
void krscaladd(int x,int y){
	krscal[krscalfind(x)]=krscal[krscalfind(y)];
	return;
}
void add(int u,int v,int w)
{
	nxt[++e_num]=head[u];
	to[e_num]=v;
	val[e_num]=w;
	head[u]=e_num;
}
int dep[M],f[M][21];
void deal(int u,int fa){
	dep[u]=dep[fa]+1;
	for(int i=0;i<=19;i++){
		f[u][i+1]=f[f[u][i]][i];
		st[u][i+1]=min(st[u][i],st[f[u][i]][i]);
	}
	for(int i=head[u];i!=0;i=nxt[i])
	{
		int v=to[i];
		if(v==fa) continue;
		f[v][0]=u;
		st[v][0]=val[i];
		deal(v,u);
	}
	return ;
}
int lca(int x,int y){
	if(find(x)!=find(y)) return -1;
	if(dep[x]<dep[y]) swap(x,y);
	int ans=2147483647;
	for(int i=20;i>=0;i--)
	{
		if(dep[f[x][i]]>=dep[y]) {x=f[x][i];ans=min(ans,st[x][i]);}
		if(x==y) return ans;
	}
	for(int i=20;i>=0;i--){
		if(f[x][i]!=f[y][i]){
			ans=min(ans, min(st[x][i],st[y][i]));
			x=f[x][i];
			y=f[y][i];
		}
	}
	return ans;
}
int main(){
	cin>>n>>m;
	memset(st,0x3f,sizeof(st));
	for(int i=1;i<=n;i++){
		b[i]=i;krscal[i]=i;
	}
	for(int i=1;i<=m;i++){
		cin>>arr[i].u>>arr[i].v>>arr[i].w;
		addd(arr[i].u,arr[i].v);
	}
	sort(arr+1,arr+1+n,cmp);
	for(int i=1;i<=m;i++){
		if(krscalfind(arr[i].u)==krscalfind(arr[i].v)) continue;
		else{
			add(arr[i].u,arr[i].v,arr[i].w);
			add(arr[i].v,arr[i].u,arr[i].w);
			krscaladd(arr[i].u,arr[i].v);
		}
	}
	deal(1,0);
	for(int i=1;i<=m;i++)
	{
		int a,b;
		cin>>a>>b;
		cout<<lca(a,b)<<"\n";
	}
	
	return 0;
}

P1967