1 //2017-08-24
  2 #include <cstdio>
  3 #include <cstring>
  4 #include <iostream>
  5 #include <algorithm>
  6 #include <queue>
  7 #pragma comment(linker, "/STACK:1024000000,1024000000") 
  8 
  9 using namespace std;
 10 
 11 const int N = 1010;
 12 const int M = 210010;
 13 const int INF = 0x3f3f3f3f;
 14 int head[N], tot;
 15 struct Edge{
 16     int next, to, w;
 17 }edge[M];
 18 
 19 void add_edge(int u, int v, int w){
 20     edge[tot].w = w;
 21     edge[tot].to = v;
 22     edge[tot].next = head[u];
 23     head[u] = tot++;
 24 }
 25 
 26 struct Dinic{
 27     int level[N], S, T;
 28     void init(int _S, int _T){
 29         S = _S;
 30         T = _T;
 31         tot = 0;
 32         memset(head, -1, sizeof(head));
 33     }
 34     bool bfs(){
 35         queue<int> que;
 36         memset(level, -1, sizeof(level));
 37         level[S] = 0;
 38         que.push(S);
 39         while(!que.empty()){
 40             int u = que.front();
 41             que.pop();
 42             for(int i = head[u]; i != -1; i = edge[i].next){
 43                 int v = edge[i].to;
 44                 int w = edge[i].w;
 45                 if(level[v] == -1 && w > 0){
 46                     level[v] = level[u]+1;
 47                     que.push(v);
 48                 }
 49             }
 50         }
 51         return level[T] != -1;
 52     }
 53     int dfs(int u, int flow){
 54         if(u == T)return flow;
 55         int ans = 0, fw;
 56         for(int i = head[u]; i != -1; i = edge[i].next){
 57             int v = edge[i].to, w = edge[i].w;
 58             if(!w || level[v] != level[u]+1)
 59                   continue;
 60             fw = dfs(v, min(flow-ans, w));
 61             ans += fw;
 62             edge[i].w -= fw;
 63             edge[i^1].w += fw;
 64             if(ans == flow)return ans;
 65         }
 66         if(ans == 0)level[u] = -1;
 67         return ans;
 68     }
 69     int maxflow(){
 70         int flow = 0, f;
 71         while(bfs())
 72               while((f = dfs(S, INF)) > 0)
 73                 flow += f;
 74         return flow;    
 75     }
 76 }dinic;
 77 
 78 char str[N];
 79 
 80 int main()
 81 {
 82     std::ios::sync_with_stdio(false);    
 83     //freopen("inputI.txt", "r", stdin);
 84     int n, m;
 85     while(cin>>n>>m){
 86         int s, t;
 87         cin>>s>>t;
 88         dinic.init(s, t+n);
 89         int u, v, w;
 90         for(int i = 1; i <= n; i++){
 91             cin>>w;
 92             add_edge(i, i+n, w);
 93             add_edge(i+n, i, 0);
 94         }
 95         while(m--){
 96             cin>>u>>v;
 97             add_edge(u+n, v, INF);
 98             add_edge(v, u+n, 0);
 99             add_edge(v+n, u, INF);
100             add_edge(u, v+n, 0);
101         }
102         printf("%d\n", dinic.maxflow());
103     }    
104     return 0;
105 }