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

#define forn(i, n) for(int i = 0; i < (int) (n); i++)
#define forsn(i, s, n) for(int i = (int) (s); i < (int) (n); i++)
#define dforn(i, n) for(int i = ((int) n) - 1; i >= 0; i--)
#define forall(i, c) for(typeof((c).begin()) i = (c).begin(); i != (c).end(); i++)

using namespace std;

//DINITZ
#define INF 1000000000
#define MAX_M 1000000
#define MAX_N 45000

int v[2*MAX_M], l[2*MAX_M];
long c[2*MAX_M];
int sz[2*MAX_N], po[MAX_N], r[MAX_N], n, S, T;

typedef map<int, long> Mii;
Mii CAP[MAX_N];

void iniG(){
    n = 0;
    memset(sz, 0, sizeof(sz));
    forn(i, MAX_N) CAP[i].clear();
}

void aEje(int d, int h, long cap){
    if(d == h) return;
    n = max(n, max(d, h));
    pair<Mii::iterator, bool> par = CAP[d].insert(make_pair(h, 0));
    if(par.second){
        CAP[h][d] = 0;
        sz[d]++, sz[h]++;
    }

    par.first->second += max(cap, (long) 0);
}

void _aEje(int d, int h, long capDH, long capHD){
#define ASIG(d, h, cap) {v[po[d]] = h; c[po[d]] = cap; l[po[d]] = po[h]; }

    ASIG(d, h, capDH);
    ASIG(h, d, capHD);
    po[d]++, po[h]++;
}

void _iniG(){
    po[0] = 0;
    forn(i, n-1) po[i+1] = po[i]+sz[i];
    forn(u, n) forall(v, CAP[u])
        if(u < v->first) _aEje(u, v->first, v->second, CAP[v->first][u]);
}

long aumentar(){
    forn(i, n) r[i] = -1;
    r[S] = 0;
    queue<int> q;
    q.push(S);
    while(!q.empty()){
        int x = q.front(); q.pop();
        int d = r[x]+1, b = po[x];
        if(r[T] >= 0 && d > r[T]) break;
        forsn(j, b, b+sz[x])
        if(c[j] > 0 && r[v[j]] < 0){
            r[v[j]] = d;
            q.push(v[j]);
        }
    }

    long res = 0;
    static int path[MAX_N]; path[0] = S;
    static int p[MAX_N], ind[MAX_N];
    memset(p, -1, sizeof(p));

    int pp = 0;
    while(pp >= 0){
        int x = path[pp];
        if(x == T){
            long f = INF;
            int pri = 0;

            dforn(i, pp) if(c[ind[i]] <= f) f=c[ind[i]],pri=i;
            forn(i, pp) c[ind[i]] -= f, c[l[ind[i]]] += f;

            res+= f;
            pp = pri;
        }else if(++p[x] < sz[x]){
            int j = po[x]+p[x];
            if(p[v[j]] < 0 && c[j] > 0 && r[v[j]] == 1 + r[x])
                ind[pp] = j, path[++pp] = v[j];
        }else pp--;
    }

    return res;
}

long flujo(int ss, int tt){
    S = ss; T = tt;
    n = max(n, max(S, T))+1;
    _iniG();
    forn(i, n) po[i] -= sz[i];

    long res = 0, c;
    do{ res += (c = aumentar());}while(c > 0);
    return res;
}

//FIN DINITZ

int main(){
#ifdef ACM
    freopen("test.in", "r", stdin);
#endif

    int g, f;
    while(scanf("%d %d\n", &g, &f) && (g != 0 || f != 0)){
        iniG();
        forn(i, g){
            int pref; scanf("%d", &pref);
            if(pref) aEje(0, 1+i, 1); else aEje(1+i, 1+g, 1);
        }

        forn(i, f){
            int a, b;
            scanf("%d %d", &a, &b); a--, b--;

            aEje(a, b, 1); aEje(b, a, 1);
        }

        long fluj = flujo(0, 1+g);
        printf("%ld\n", fluj);
    }

    return 0;
}