#include<iostream>
#include<cstdio>
#include<cstring>
#include<queue>

using namespace std;

const int VM=420;
const int EM=500010;
const int INF=0x3f3f3f3f;

struct Edge{
    int to,nxt;
    int cap;
}edge[EM];

int n,m,src,des,cnt,head[VM];
int dep[VM];

void addedge(int cu,int cv,int cw){
    edge[cnt].to=cv;    edge[cnt].cap=cw;   edge[cnt].nxt=head[cu];
    head[cu]=cnt++;
    edge[cnt].to=cu;    edge[cnt].cap=0;    edge[cnt].nxt=head[cv];
    head[cv]=cnt++;
}

int BFS(){
    queue<int> q;
    while(!q.empty())
        q.pop();
    memset(dep,-1,sizeof(dep));
    dep[src]=0;
    q.push(src);
    while(!q.empty()){
        int u=q.front();
        q.pop();
        for(int i=head[u];i!=-1;i=edge[i].nxt){
            int v=edge[i].to;
            if(edge[i].cap>0 && dep[v]==-1){
                dep[v]=dep[u]+1;
                q.push(v);
            }
        }
    }
    return dep[des]!=-1;
}

int DFS(int u,int minx){
    if(u==des)
        return minx;
    int tmp;
    for(int i=head[u];i!=-1;i=edge[i].nxt){
        int v=edge[i].to;
        if(edge[i].cap>0 && dep[v]==dep[u]+1 && (tmp=DFS(v,min(minx,edge[i].cap)))){
            edge[i].cap-=tmp;
            edge[i^1].cap+=tmp;
            return tmp;
        }
    }
    dep[u]=-1;
    return 0;
}

int Dinic(){
    int ans=0,tmp;
    while(BFS()){
        while(1){
            tmp=DFS(src,INF);
            if(tmp==0)
                break;
            ans+=tmp;
        }
    }
    return ans;
}

int main(){
    int s,t;
    while(~scanf("%d%d",&n,&m)){
        cnt=0;
        memset(head,-1,sizeof(head));
        scanf("%d%d",&s,&t);
        src=0, des=2*n+1;
        addedge(src,s,INF);
        addedge(n+t,des,INF);
        int u,v,w;
        for(int i=1;i<=n;i++){
            scanf("%d",&w);
            addedge(i,n+i,w);
            addedge(n+i,i,w);
        }
        for(int i=1;i<=m;i++){
            scanf("%d%d",&u,&v);
            addedge(n+u,v,INF);     //注意这里的建边,src--->s--->u(某条边)---->n+u(拆分u点后的另一点)---->v---->n+v(拆分v点后的另一点)---->u-----
            addedge(n+v,u,INF);     //所以，addedge(n+u,v,INF);仔细想想，这样才能保证 u 和 v 使连接着的
        }
        printf("%d\n",Dinic());
    }
    return 0;
}