1 #include<cstdio>
 2 #include<algorithm>
 3 #include<stack>
 4 #include<cstring>
 5 #define maxn 4000
 6
 7 using namespace std;
 8
 9 int n,p,tot,r,dfs_clock,scc_cnt,ans;
10 int head[maxn],val[maxn],rdu[maxn],dfn[maxn],low[maxn],scc[maxn],price[maxn];
11 bool buy[maxn];
12 struct node{
13     int to,next;
14 }edge[maxn*2];
15 stack<int>s;
16
17 void add(int x,int y)
18 {
19     edge[++tot].to=y;
20     edge[tot].next=head[x];
21     head[x]=tot;
22 }
23
24 void tarjan(int u)
25 {
26     dfn[u]=low[u]=++dfs_clock;
27     s.push(u);
28     for(int i=head[u];i;i=edge[i].next)
29     {
30         int v=edge[i].to;
31         if(!dfn[v])
32         {
33             tarjan(v);
34             low[u]=min(low[u],low[v]);
35         }
36         else if(!scc[v]) low[u]=min(low[u],dfn[v]);
37     }
38     if(dfn[u]==low[u])
39     {
40         scc_cnt++;
41         while(1)
42         {
43             int x=s.top();s.pop();
44             scc[x]=scc_cnt;
45             val[scc_cnt]=min(val[scc_cnt],price[x]);
46             if(x==u) break;
47         }
48     }
49 }
50
51 int main()
52 {
53     scanf("%d%d",&n,&p);
54     memset(price,127,sizeof(price));
55     memset(val,127,sizeof(val));
56     for(int i=1;i<=p;i++)
57     {
58         int x=0;
59         scanf("%d",&x);
60         buy[x]=1;
61         scanf("%d",&price[x]);
62     }
63     scanf("%d",&r);
64     for(int i=1;i<=r;i++)
65     {
66         int x=0,y=0;
67         scanf("%d%d",&x,&y);
68         add(x,y);
69     }
70     for(int i=1;i<=n;i++)
71         if(!dfn[i]&&buy[i]) tarjan(i);
72     for(int i=1;i<=n;i++)
73         if(!dfn[i]){ans=i;break;}
74     if(ans) {printf("NO\n%d",ans);return 0;}
75     printf("YES\n");
76     for(int x=1;x<=n;x++)
77         for(int i=head[x];i;i=edge[i].next)
78         {
79             int y=edge[i].to;
80             if(scc[x]==scc[y]) continue;
81             rdu[scc[y]]++;
82         }
83     for(int i=1;i<=scc_cnt;i++)
84         if(rdu[i]==0) ans+=val[i];
85     printf("%d",ans);
86     return 0;
87 }