#include<iostream>

#include<cstdio>

#include<cstring>

#include<algorithm>

using namespace std;

int const xn=,xm=,inf=0x3f3f3f3f;

int n,m,hd[xn],ct,to[xm],nxt[xm],fr[xm],dfn[xn],low[xn],tim,sta[xn],top;

int deg[xn],col[xn],cr,hd2[xn],ct2,to2[xm],nxt2[xm],p,w[xn],ans,mn[xn],mi[xn];

bool vis[xn];

void add(int x,int y){to[++ct]=y; fr[ct]=x; nxt[ct]=hd[x]; hd[x]=ct;}

void add2(int x,int y){to2[++ct2]=y; nxt2[ct2]=hd2[x]; hd2[x]=ct2;}

int rd()

{

    int ret=,f=; char ch=getchar();

    while(ch<''||ch>''){if(ch=='-')f=; ch=getchar();}

    while(ch>=''&&ch<='')ret=(ret<<)+(ret<<)+ch-'',ch=getchar();

    return f?ret:-ret;

}

void tarjan(int x)

{

    dfn[x]=low[x]=++tim; vis[x]=; sta[++top]=x;

    for(int i=hd[x],u;i;i=nxt[i])

    {

        if(!dfn[u=to[i]])tarjan(u),low[x]=min(low[x],low[u]);

        else if(vis[u])low[x]=min(low[x],dfn[u]);

    }

    if(dfn[x]==low[x])

    {

        int y; cr++; mn[cr]=inf; mi[cr]=inf;

        while((y=sta[top])!=x)

            col[y]=cr,vis[y]=,top--,mn[cr]=min(mn[cr],w[y]),mi[cr]=min(mi[cr],y);

        col[x]=cr; vis[x]=; top--;

        mn[cr]=min(mn[cr],w[x]); mi[cr]=min(mi[cr],x);

    }

}

int find(int x)

{

    int ret=mi[x];

    for(int i=hd2[x];i;i=nxt2[i])

    {

        if(mn[to2[i]]!=inf)break;//!

        ret=min(ret,find(to2[i]));

    }

    return ret;

}

int main()

{

    n=rd(); p=rd();

    memset(w,0x3f,sizeof w);

    for(int i=,id;i<=p;i++)id=rd(),w[id]=rd();

    m=rd();

    for(int i=,x,y;i<=m;i++)

    {

        x=rd(); y=rd();

        add(x,y);

    }

        //add(x=rd(),y=rd()),printf("add(%d,%d)\n",x,y);

    for(int i=;i<=n;i++)if(!dfn[i])tarjan(i);

    for(int i=,u,v;i<=ct;i++)

        if((u=col[fr[i]])!=(v=col[to[i]]))add2(u,v),deg[v]++;

    bool fl=; int id=inf;

    for(int i=;i<=cr;i++)

    {

        if(deg[i])continue;

        if(mn[i]==inf)fl=,id=min(id,find(i));

        else ans+=mn[i];

    }

    if(fl)printf("NO\n%d\n",id);

    else printf("YES\n%d\n",ans);

    return ;

}