TLE on #4。

#include<bits/stdc++.h>
#define int long long
using namespace std;
namespace fast_IO{
	#define FASTIO
	#define IOSIZE 100000
	char ibuf[IOSIZE],obuf[IOSIZE];char*p1=ibuf,*p2=ibuf,*p3=obuf;
	#ifdef ONLINE_JUDGE
	#define getchar()((p1==p2)and(p2=(p1=ibuf)+fread(ibuf,1,IOSIZE,stdin),p1==p2)?(EOF):(*p1++))
	#define putchar(x)((p3==obuf+IOSIZE)&&(fwrite(obuf,p3-obuf,1,stdout),p3=obuf),*p3++=x)
	#endif
	#define isdigit(ch)(ch>47&&ch<58)
	#define isspace(ch)(ch<33)
	template<typename T>inline T read(){T s=0;int w=1;char ch;while(ch=getchar(),!isdigit(ch)and(ch!=EOF))if(ch=='-')w=-1;if(ch==EOF)return false;while(isdigit(ch))s=s*10+ch-48,ch=getchar();return s*w;}template<typename T>inline bool read(T&s){s=0;int w=1;char ch;while(ch=getchar(),!isdigit(ch)and(ch!=EOF))if(ch=='-')w=-1;if(ch==EOF)return false;while(isdigit(ch))s=s*10+ch-48,ch=getchar();return s*=w,true;}inline bool read(char&s){while(s=getchar(),isspace(s));return true;}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>inline void print(T x){if(x<0)putchar('-'),x=-x;if(x>9)print(x/10);putchar(x%10+48);}inline void print(char x){putchar(x);}inline void print(char*x){while(*x)putchar(*x++);}inline void print(const char*x){for(int i=0;x[i];i++)putchar(x[i]);}
	#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(int i=0,n=x.size();i<n;i++)putchar(x[i]);}
	#endif
	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...);}struct Fast_IO{~Fast_IO(){fwrite(obuf,p3-obuf,1,stdout);}}io;template<typename T>Fast_IO&operator>>(Fast_IO&io,T&b){return read(b),io;}template<typename T>Fast_IO&operator<<(Fast_IO&io,T b){return print(b),io;}
}using namespace fast_IO;
#define cin io
#define cout io
#define endl '\n' 
map<int, bool >bj;
int p[105];
struct Greater_Heap {
	int heap[1000005], pos[1000005], id[1000005], h_size;
	inline void Swap(int a, int b) {
	    swap(pos[id[a]], pos[id[b]]);
	    swap(id[a], id[b]);
	    swap(heap[a], heap[b]);
	}
	inline void HeapDown(int u) {
	    int t = u;
	    if(u * 2 <= h_size && heap[u * 2] < heap[t]) t = u * 2;
	    if(u * 2 + 1 <= h_size && heap[u * 2 + 1] < heap[t]) t = u * 2 + 1;
	    if(u != t) {
	        Swap(u, t);
	        HeapDown(t);
	    }
	}
	inline void HeapUp(int u) {
	    while(u / 2 && heap[u / 2] > heap[u]) {
	        Swap(u / 2, u);
	        u /= 2;
	    }
	}
	inline void insert(int x) {
		h_size++;
	    heap[0]++;
	    pos[heap[0]] = h_size;
		id[h_size] = heap[0];
	    heap[h_size] = x;
	    HeapUp(h_size);
	}
	inline void del(int k) {
		k = pos[k];
	    Swap(k, h_size);
	    h_size--;
	    HeapDown(k);
		HeapUp(k);
	}
	inline void modify(int k, int x) {
		k = pos[k];
	    heap[k] = x;
	    HeapDown(k);
		HeapUp(k);
	}
}h;
int k, n, tot;
signed main() {
	cin >> k >> n; 
	for(int i = 1; i <= k; i++) {
		cin >> p[i];
	}
	h.insert(1);
	bj[1] = 1;
	int t;
	while(tot <= n) {
		t = h.heap[1];
		//cout << "min: " << t << endl;
		h.del(h.id[1]);
		for(int i = 1; i <= k; i++) 
			if(!bj[t * p[i]]) bj[t * p[i]] = 1, h.insert(t * p[i]);
		tot++;
	} 
	cout << t;
	return 0;
}