int edge[MAXM],pre[MAXN]={0},next[MAXM],weight[MAXM],size=1;
void addedge(int u,int v,int w)
{
edge[++size]=v;
weight[size]=w;
next[size]=pre[u];
pre[u]=size;
}
void addedge2(int u,int v,int w){addedge(u,v,w),addedge(v,u,0);}
int d[MAXN]={0},cnt[MAXN]={0},s,t;
int totflow=0;
int sap(int x,int flow)
{
if (x==t) return flow;
int nowflow=0;
Forp(x)
{
int &v=edge[p];
if (d[v]==d[x]-1&&weight[p]>0)
{
int fl=sap(v,min(flow,weight[p]));
weight[p]-=fl,weight[p^1]+=fl,flow-=fl,nowflow+=fl;
if (!flow) return nowflow;
}
}
if (!(--cnt[d[x]++])) d[s]=t+1;
return nowflow;
}
int n,m,a[MAXN];
int main()
{
// freopen("conflict.in","r",stdin);
// freopen("conflict.out","w",stdout);
scanf("%d%d",&n,&m);
s=n+1,t=s+1;
For(i,n)
{
scanf("%d",&a[i]);
if (a[i]) addedge2(s,i,1);
else addedge2(i,t,1);
}
For(i,m)
{
int u,v;
scanf("%d%d",&u,&v);
addedge(u,v,1);addedge(v,u,1);
}
cnt[0]=n+2;
while (d[s]<=t) totflow+=sap(s,INF);
cout<
return 0;
}