1 #include <iostream>
 2 #include <cstring>
 3 #include <cstdio>
 4 #include <queue>
 5 using namespace std;
 6 inline int read(){
 7     int sum(0);char ch(getchar());
 8     for(;ch<‘0‘||ch>‘9‘;ch=getchar());
 9     for(;ch>=‘0‘&&ch<=‘9‘;sum=sum*10+(ch^48),ch=getchar());
10     return sum;
11 }
12 struct edge{int e,w;edge *n,*rev;}*pre[405];
13 inline void insert(int s,int e,int w){
14     edge *tp1(new edge),*tp2(new edge);
15     tp1->e=e;tp1->w=w;tp1->rev=tp2;tp1->n=pre[s];pre[s]=tp1;
16     tp2->e=s;tp2->w=0;tp2->rev=tp1;tp2->n=pre[e];pre[e]=tp2;
17 }
18 const int inf(0x3f3f3f3f);
19 int n,m,a,b,S,T,ans,dis[405];
20 queue<int>q;
21 inline bool bfs(){
22     memset(dis,0,sizeof(dis));while(!q.empty())q.pop();dis[S]=1;q.push(S);
23     while(!q.empty()){
24         int k(q.front());q.pop();
25         for(edge *i=pre[k];i;i=i->n)
26             if(i->w&&!dis[i->e]){
27                 dis[i->e]=dis[k]+1;
28                 if(i->e==T)return true;
29                 q.push(i->e);
30             }
31     }
32     return false;
33 }
34 inline int dfs(int u,int f){
35     if(u==T||!f)return f;
36     int ret(0);
37     for(edge *i=pre[u];i;i=i->n)
38         if(i->w&&dis[i->e]==dis[u]+1){
39             int tmp(dfs(i->e,min(i->w,f-ret)));
40             i->w-=tmp;i->rev->w+=tmp;ret+=tmp;
41             if(ret==f)break;
42         }
43     return ret;
44 }
45 int main(){
46     n=read(),m=read(),a=read(),b=read();S=0,T=(n<<1)+1;
47     insert(S,a,inf);insert(b+n,T,inf);
48     for(int i=1;i<=n;++i){int x(read());insert(i,i+n,x);}
49     for(int i=1;i<=m;++i){
50         int x(read()),y(read());
51         insert(x+n,y,inf);insert(y+n,x,inf);
52     }
53     while(bfs())ans+=dfs(S,inf);
54     printf("%d",ans);
55 }