//Twenty
#include<cstdio>
#include<cstdlib>
#include<iostream>
#include<algorithm>
#include<cmath>
#include<cstring>
#include<queue>
#include<vector>
const int maxn=20050,maxm=200050,INF=0x7f7f7f7f;
using namespace std;
int n,m,s,t,u,v,w,ecnt=1,fir[maxn],d[maxn],cur[maxn],c[maxn],p[maxn];
struct edge {int from,to,cap,flow,nxt;edge(){}edge(int from,int to,int cap,int flow,int nxt):from(from),to(to),cap(cap),flow(flow),nxt(nxt){}
}e[maxm];
void add(int u,int v,int w) {e[++ecnt]=edge(u,v,w,0,fir[u]);     e[++ecnt]=edge(v,u,0,0,fir[v]); fir[u]=ecnt-1; fir[v]=ecnt;
}
queue<int>que;
void bfs(int s,int t) {for(int i=1;i<=n;i++) d[i]=n;d[t]=0; que.push(t);while(!que.empty()) {int x=que.front() ;que.pop();for(int i=fir[x];i;i=e[i].nxt) if(d[e[i].to]==n&&e[i].flow==e[i].cap) {d[e[i].to]=d[x]+1;que.push(e[i].to); }}
}
int cal(int s,int t) {int fl=INF;for(int x=t;x!=s;x=e[p[x]].from) fl=min(fl,e[p[x]].cap-e[p[x]].flow);for(int x=t;x!=s;x=e[p[x]].from) {e[p[x]].flow+=fl;e[p[x]^1].flow-=fl;}return fl;
}
int maxflow(int s,int t) {bfs(s,t);int res=0;for(int i=1;i<=n;i++) cur[i]=fir[i],c[d[i]]++;for(int x=s;d[x]<n;) {if(x==t) {res+=cal(s,t);x=s;}int ok=0;for(int &i=cur[x];i;i=e[i].nxt) if(d[e[i].to]+1==d[x]&&e[i].cap>e[i].flow){p[x=e[i].to]=i;ok=1; break;}if(!ok) {cur[x]=fir[x]; int M=n;for(int i=cur[x];i;i=e[i].nxt) if(e[i].cap>e[i].flow)M=min(M,d[e[i].to]+1);if(!(--c[d[x]])) break;c[d[x]=M]++;if(x!=s) x=e[p[x]].from;}}return res;
}
int main()
{scanf("%d%d",&n,&m);s=n+1; t=n+2;for(int i=1;i<=n;i++) {int x;scanf("%d",&x);if(x==1) add(s,i,1),add(i,t,0);else add(s,i,0),add(i,t,1);}n+=2;for(int i=1;i<=m;i++) {int x,y;scanf("%d%d",&x,&y);add(x,y,1);add(y,x,1);}printf("%d\n",maxflow(s,t));return 0;
}