bzoj1934

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cstring>
#include<queue>
#define ll long long
#define N 305
using namespace std;
int n,m,S,T,tot,hd[N],d[N],vis[N],cur[N];
struct edge{int v,next,cap,flow;}e[N*N*4];
void adde(int u,int v,int c){
    e[tot].v=v;
    e[tot].next=hd[u];
    e[tot].cap=c;
    e[tot].flow=0;
    hd[u]=tot++;
}

bool bfs(){
    queue<int>q;
    memset(vis,0,sizeof(vis));
    q.push(S);d[S]=0;
    while(!q.empty()){
        int u=q.front();q.pop();vis[u]=1;
        for(int i=hd[u];~i;i=e[i].next){
            int v=e[i].v;
            if(e[i].cap<=e[i].flow||vis[v])continue;
            d[v]=d[u]+1;q.push(v);
        }
    }
    return vis[T];
}

int dfs(int u,int a){
    if(u==T||!a)return a;
    int fl=0,f;
    for(int i=hd[u];~i;i=e[i].next){
        int v=e[i].v;
        if(d[v]==d[u]+1&&(f=dfs(v,min(e[i].cap-e[i].flow,a)))){
            fl+=f;a-=f;
            e[i].flow+=f;
            e[i^1].flow-=f;
            if(a<=0)break;
        }
    }
    return fl;
}
int main(){
    scanf("%d%d",&n,&m);
    memset(hd,-1,sizeof(hd));
    S=0;T=n+1;
    for(int i=1;i<=n;i++){
        int x;
        scanf("%d",&x);
        if(x)adde(S,i,1),adde(i,S,0);
        else adde(i,T,1),adde(T,i,0);
    }
    for(int i=1;i<=m;i++){
        int a,b;
        scanf("%d%d",&a,&b);
        adde(a,b,1);adde(b,a,1);
    }
    int flow=0;
    while(bfs()){
        for(int i=S;i<=T;i++)cur[i]=hd[i];
        flow+=dfs(S,0x3f3f3f3f);
    }
    printf("%d",flow);
    return 0;
}