#include <bits/stdc++.h>//优化了当前弧）
using namespace std;
typedef long long LL;
const int N=510,M=250000;
struct node{int x,y;LL f; int pre;}a[M];int alen,last[N],cur[N];
void ins(int x,int y,LL f)
{
    alen++;a[alen]=node{x,y,f,last[x]};last[x]=alen;
    alen++;a[alen]=node{y,x,0,last[y]};last[y]=alen;
}

int h[N],st,ed,n,m;
bool bfs()
{
    deque<int>q;q.clear();
    memset(h,0,sizeof(h));h[st]=1;
    q.push_back(st);
    while(!q.empty())
    {
        int x=q.front();q.pop_front();
        for(int k=last[x];k>0;k=a[k].pre)if(a[k].f)
        {
            int y=a[k].y;
            if(h[y]==0)
            {
                h[y]=h[x]+1;
                q.push_back(y);
            }
        }
    }
    return h[ed]>0;
}

LL dinic(int x,LL f)
{
    if(x==ed)return f;
    LL sx=0;
    for(int k=cur[x];k;k=a[k].pre)if(a[k].f)
    {
        int y=a[k].y;
        cur[x]=k;//k之前的边对于x已经没有意义 
        if(h[y]==h[x]+1)
        {
            LL sy=dinic(y,min(a[k].f,f-sx));
            a[k].f-=sy;a[k^1].f+=sy;
            sx+=sy;if(sx==f)return f;
        }
    }
    if(sx==0)h[x]=0;
    return sx;
}
int main()
{
    scanf("%d%d%d%d",&n,&m,&st,&ed);ed+=n;
    alen=1;memset(last,0,sizeof(last));
    for(int i=1,x;i<=n;i++)
    {
        scanf("%d",&x);
        ins(i,n+i,x);

    }
    for(int i=1,x,y;i<=m;i++)
    {
        scanf("%d%d",&x,&y);
        ins(n+x,y,1LL<<60);
        ins(n+y,x,1LL<<60);
    }
    LL s=0;
    while( bfs() )
    {
        memcpy(cur,last,sizeof(int)*(2*n+2)); 
        s+=dinic(st,(LL)1<<62);
    }
    printf("%lld",s);
    return 0;
}