#include <cstdio>
#include <cstdlib>
#include <cstring>
struct
{int x,y,n;
}e[100001];
int f[3001];
int o;
bool v[3001];
bool vs[1001];
int b[3001][3001],dfn[3001],low[3001],zhan=0,lian,ti=0;
int stick[3001],money[3001];
int into[3001];
bool map[3001][3001];
int intot[3001];
int min(int a,int b)
{return (a<b)?a:b;
}
void add(int a,int b)
{o++;e[o].x=a;e[o].y=b;e[o].n=f[a];f[a]=o;
}
void tanzhan(int u)
{lian++;int j=1;while (stick[zhan]!=u){b[lian][j++]=stick[zhan--];vs[stick[zhan]]=false;}b[lian][j++]=stick[zhan--];vs[u]=false;b[lian][0]=j-1;
}
void tarjan(int u)
{dfn[u]=++ti;if (low[u]==0) low[u]=dfn[u];stick[++zhan]=u;vs[u]=true;int t=f[u];v[u]=true;while (e[t].y!=0){if (v[e[t].y]==false) { tarjan(e[t].y);low[u]=min(low[u],low[e[t].y]);}else{if (vs[e[t].y]==true)low[u]=min(low[u],dfn[e[t].y]);}     t=e[t].n;           }if (dfn[u]==low[u]) tanzhan(u);
}
int main()
{freopen("tarjan.in","r",stdin);freopen("tarjan.out","w",stdout);int n;memset(map,0,sizeof(map));scanf("%d",&n);int p;scanf("%d",&p);for (int i=1;i<=p;i++){int a,b;scanf("%d%d",&a,&b);if (money[a]==0||b<money[a])money[a]=b;}int r;scanf("%d",&r);for (int i=1;i<=r;i++){int a,b;scanf("%d%d",&a,&b);add(a,b);into[b]++;map[a][b]=1;}for (int i=1;i<=n;i++)if (v[i]==false) tarjan(i);for (int i=1;i<=lian;i++){intot[i]=0;for (int j=1;j<=b[i][0];j++)for (int k=1;k<=b[i][0];k++)if (k!=j){if (map[b[i][j]][b[i][k]]==1) into[b[i][k]]--;}for (int j=1;j<=b[i][0];j++)if (into[b[i][j]]>0) intot[i]=1;}int sum=0;int cant=100000000;for (int i=1;i<=lian;i++){if (intot[i]==0){int maxx=100000000;for (int j=1;j<=b[i][0];j++)if (money[b[i][j]]!=0&&money[b[i][j]]<maxx) maxx=money[b[i][j]];if (maxx==100000000){  for (int j=1;j<=b[i][0];j++)if (b[i][j]<cant) cant=b[i][j];}else if (maxx!=100000000) sum+=maxx;}}if (cant==100000000){printf("YES\n");printf("%d\n",sum);}else{printf("NO\n");        printf("%d\n",cant);}return 0;
}