#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<stack>
using namespace std;
const int N=1e3*3+5;
int n,p,op,mon,mey[N],r,A,B,h[N],cnt,dfn[N],low[N],dian,id[N],w[N],chu[N],ru[N],ans,mm[N],o=1e5;
stack<int> sta;
bool b[N];
struct qwe{
	int to,net;
}tr[N*2]; 
void add(int x,int y){
	tr[++cnt].to=y;
	tr[cnt].net=h[x];
	h[x]=cnt;
} 
void df(int x){
	dfn[x]=low[x]=++cnt;b[x]=1;sta.push(x);
	for(int i=h[x];i;i=tr[i].net){
		int y=tr[i].to;
		if(!dfn[y]){
			df(y);
			low[x]=min(low[x],low[y]);
		}
		else if(b[y]) low[x]=min(low[x],dfn[y]);
	}
	if(dfn[x]==low[x]){
		++dian;
		id[x]=dian;
		b[x]=0;
		w[dian]=mey[x];mm[dian]=x;
		while(sta.top()!=x){
			w[dian]=min(w[dian],mey[sta.top()]);
			mm[dian]=min(mm[dian],sta.top());
			b[sta.top()]=0;
			sta.pop();
		}
		sta.pop();
	}
}
int main(){
	scanf("%d",&n);
	scanf("%d",&p);
	memset(mey,127,sizeof(mey));
	for(int i=1;i<=p;i++){
		scanf("%d%d",&op,&mon);
		mey[op]=mon;
	}
	scanf("%d",&r);
	for(int i=1;i<=r;i++){
		scanf("%d%d",&A,&B);
		add(A,B);
	}
	cnt=0;
	for(int i=1;i<=n;i++) if(!dfn[i]) df(i);
	for(int i=1;i<=n;i++){
		for(int j=h[i];j;j=tr[j].net){
			int y=tr[j].to;
			if(id[i]!=id[y]){
				chu[id[i]]++;
				ru[id[y]]++;
			}
		}
	}
	for(int i=1;i<=dian;i++){
		if(!ru[i]) ans+=w[i];
		if(ans>=2139062143&&o>mm[i]){
			o=mm[i];
		}
	}
	if(ans>=2139062143) puts("NO"),printf("%d\n",o);
	else puts("YES"),printf("%d\n",ans);
	return 0;
}