#include <iostream>
#include <cstdio>
#include <cstring>
#include <vector>
#include <string>
#include <algorithm>
#include <queue>
using namespace std;
const int maxn = 1000;
const int maxe = 20000*10;
const int inf = 1<<30;
int n,m,s,d;
int src,sink;
queue<int> que;
bool vis[maxn];
int dist[maxn];
struct edge{
    int v,f,nxt;
}e[maxe];
int head[maxn];
int nume;
void addedge(int u,int v,int w){
    e[++nume].nxt = head[u];
    e[nume].v = v;
    e[nume].f = w;
    head[u] = nume;
    e[++nume].nxt = head[v];
    e[nume].v = u;
    e[nume].f = 0;
    head[v] = nume;
}
void bfs(){
    memset(dist,0,sizeof dist);
    while(!que.empty()) que.pop();
    vis[src] = true;
    que.push(src);
    while(!que.empty()){
        int u = que.front();
        que.pop();
        for(int i = head[u]; i ; i = e[i].nxt){
            if(e[i].f && !vis[e[i].v]){
                que.push(e[i].v);
                vis[e[i].v] = 1;
                dist[e[i].v] = dist[u]+1;
            }
        }
    }
}

int dfs(int u,int delta){
    if(u== sink) return delta;
    else{
        int ret = 0;
        for(int i = head[u]; delta&&i; i = e[i].nxt){
            if(e[i].f && dist[e[i].v] == dist[u]+1){
                int dd = dfs(e[i].v,min(e[i].f,delta));
                e[i].f -= dd;
                e[i^1].f += dd;
                delta -= dd;
                ret += dd;
            }
        }
        return ret;
    }
}

int maxflow(){
    int ret = 0;
    while(true){
        memset(vis,0,sizeof vis);
        bfs();
        if(!vis[sink]) return ret;
        ret += dfs(src,inf);
    }

}
void init(){
    memset(head,0,sizeof head);
    nume = 1;
}
int main(){

    while(~scanf("%d%d",&n,&m)){
        init();
        scanf("%d%d",&s,&d);
        src = 2*s-1;
        sink = 2*d;
        for(int i = 1; i <= n; i++){
            int t;
            scanf("%d",&t);
            addedge(i*2-1,i*2,t);
        }
        while(m--){
            int a,b;
            scanf("%d%d",&a,&b);
            addedge(a*2,2*b-1,inf);
            addedge(2*b,a*2-1,inf);
        }
        printf("%d\n",maxflow());
    }
    return 0;
}