#include<bits/stdc++.h>
using namespace std;
//input by bxd
#define rep(i,a,b) for(int i=(a);i<=(b);i++)
#define repp(i,a,b) for(int i=(a);i>=(b);--i)
#define RI(n) scanf("%d",&(n))
#define RII(n,m) scanf("%d%d",&n,&m)
#define RIII(n,m,k) scanf("%d%d%d",&n,&m,&k)
#define RS(s) scanf("%s",s);
#define ll long long
#define pb push_back
#define REP(i,N)  for(int i=0;i<(N);i++)
#define CLR(A,v)  memset(A,v,sizeof A)
//
#define inf 0x3f3f3f3f
const int N=4e6+44;
const int M=4e6+54;struct edge {int to, next, w;
} e[M << 1];
int head[N], cnt = 1;
void add(int x, int y, int z) {e[++cnt] = (edge){y, head[x], z};head[x] = cnt;e[++cnt] = (edge){x, head[y], 0};head[y] = cnt;
}
int level[N];
bool bfs(int s, int t) {memset(level, 0, sizeof level);queue<int> q;level[s] = 1;q.push(s);while (!q.empty()) {int pos = q.front();q.pop();for (int i = head[pos]; i; i = e[i].next) {int nx = e[i].to;if (!e[i].w || level[nx]) continue;level[nx] = level[pos] + 1;q.push(nx);}}return level[t];
}
int dfs(int s, int t, int flow) {if (s == t) return flow;int ret = 0;for (int i = head[s]; flow && i; i = e[i].next) {int nx = e[i].to;if (level[nx] == level[s] + 1 && e[i].w) {int tmp = dfs(nx, t, min(flow, e[i].w));e[i].w -= tmp;e[i ^ 1].w += tmp;flow -= tmp;ret += tmp;}}if (!ret) level[s] = 0;return ret;
}
int dinic(int s, int t) {int ret = 0;while (bfs(s, t)) ret += dfs(s, t, inf);return ret;
}
int n,m,s,t,sum;
int dx[]={0,0,1,-1};
int dy[]={1,-1,0,0};
int id(int x,int y)
{return (x-1)*m+y;
}
int main()
{RII(n,m);s=n+1;t=s+1;rep(i,1,n){int x;RI(x);if(x==1)add(s,i,1);else add(i,t,1);}while(m--){int a,b;RII(a,b);add(a,b,1);add(b,a,1);}cout<<dinic(s,t);
}