#include<bits/stdc++.h>
using namespace std;
const int N=3e3+10;
vector<int>G[N];
int c[N],cc[N];
int tsp,cnt,dfn[N],low[N],scc[N];
stack<int> stk;bool instk[N];
void tarjan(int x)
{
    dfn[x]=low[x]=++tsp;
    stk.push(x);instk[x]=1; 
    for(int y:G[x])
	{
        if(!dfn[y])
        {
            tarjan(y);
            low[x]=min(low[x],low[y]);
        }
        else if(instk[y]) low[x]=min(low[x],dfn[y]);
    }
    if(dfn[x]==low[x])
    {
        cnt++;
        for(int z=-1;z!=x;)
        {
            z=stk.top();stk.pop();instk[z]=0;
            scc[z]=cnt;
            cc[cnt]=min(c[z],cc[cnt]);
        }
    }
}
int main()
{
    int n,m,p;scanf("%d%d",&n,&p);
    memset(c,0x3f,sizeof(c));
    for(int i=1,x;i<=p;i++){scanf("%d",&x);scanf("%d",&c[x]);}
     
    scanf("%d",&m);
    memset(G,0,sizeof(G));
    for(int i=1,x,y;i<=m;i++)scanf("%d%d",&x,&y),G[x].push_back(y);
     
    tsp=cnt=0;memset(dfn,0,sizeof(dfn));memset(low,0,sizeof(low));
    memset(scc,0,sizeof(scc));memset(instk,false,sizeof(instk));
    memset(cc,0x3f,sizeof(cc));
    for(int i=1;i<=n;i++) if(!dfn[i] && c[i]!=0x3f3f3f3f) tarjan(i);
     
    vector<int>rd(cnt+1);
    for(int i=1,x,y;i<=n;i++)for(int j:G[i])if(scc[i]!=scc[j]) rd[scc[j]]++;
     
    for(int i=1;i<=n;i++)if(scc[i]==0){printf("NO\n%d",i);return 0;}

    int ans=0;for(int i=1;i<=cnt;i++)if(rd[i]==0)ans+=cc[i];
    printf("YES\n%d",ans);

    return 0;
}

#include<bits/stdc++.h>
using namespace std;
const int N=3e3+10;
vector<int>G[N];
int c[N],cc[N];
int tsp,cnt,dfn[N],low[N],scc[N];
stack<int> stk;bool instk[N];
void tarjan(int x)
{
    dfn[x]=low[x]=++tsp;
    stk.push(x);instk[x]=1; 
    for(int y:G[x])
	{
        if(!dfn[y])
        {
            tarjan(y);
            low[x]=min(low[x],low[y]);
        }
        else if(instk[y]) low[x]=min(low[x],dfn[y]);
    }
    if(dfn[x]==low[x])
    {
        cnt++;
        for(int z=-1;z!=x;)
        {
            z=stk.top();stk.pop();instk[z]=0;
            scc[z]=cnt;
            cc[cnt]=min(c[z],cc[cnt]);
        }
    }
}
int main()
{
    int n,m,p;scanf("%d%d",&n,&p);
    memset(c,0x3f,sizeof(c));
    for(int i=1,x;i<=p;i++){scanf("%d",&x);scanf("%d",&c[x]);}
     
    scanf("%d",&m);
    memset(G,0,sizeof(G));
    for(int i=1,x,y;i<=m;i++)scanf("%d%d",&x,&y),G[x].push_back(y);
     
    tsp=cnt=0;memset(dfn,0,sizeof(dfn));memset(low,0,sizeof(low));
    memset(scc,0,sizeof(scc));memset(instk,False,sizeof(instk));
    memset(cc,0x3f,sizeof(cc));
    for(int i=1;i<=n;i++) if(!dfn[i] && c[i]!=0x3f3f3f3f) tarjan(i);
     
    vector<int>rd(cnt+1);
    for(int i=1,x,y;i<=n;i++)for(int j:G[i])if(scc[i]!=scc[j]) rd[scc[j]]++;
     
    for(int i=1;i<=n;i++)if(scc[i]==0){printf("NO\n%d",i);return 0;}

    int ans=0;for(int i=1;i<=cnt;i++)if(rd[i]==0)ans+=cc[i];
    printf("YES\n%d",ans);

    return 0;
}