#include<bits/stdc++.h>

using namespace std;

#define N 310

typedef long long ll;

typedef long double ld;

typedef unsigned long long ull;

const int inf = 1e9;

struct edge

{

    int to , w , nxt;

} e[N * N * ];

int tot , n , m , S , T;

int head[N] , dep[N];

template <typename T> inline void chkmin(T &x , T y) { x = min(x , y); }

template <typename T> inline void chkmax(T &x , T y) { x = max(x , y); }

template <typename T> inline void read(T &x)

{

   T f = ; x = ;

   char c = getchar();

   for (; !isdigit(c); c = getchar()) if (c == '-') f = -f;

   for (; isdigit(c); c = getchar()) x = (x << ) + (x << ) + c - '';

   x *= f;

}

inline void addedge(int u , int v , int w)

{

    ++tot;

    e[tot] = (edge){v , w , head[u]};

    head[u] = tot;

    ++tot;

    e[tot] = (edge){u ,  , head[v]};

    head[v] = tot;

}

inline bool bfs(int s)

{

    queue< int > q;

    memset(dep ,  , sizeof(dep));

    q.push(s);

    dep[s] = ;

    while (!q.empty())

    {

        int cur = q.front();

        q.pop();

        for (int i = head[cur]; i; i = e[i].nxt)

        {

            int v = e[i].to , w = e[i].w;

            if (w >  && dep[v] == -)

            {

                dep[v] = dep[cur] + ;

                q.push(v);

                if (v == T) return true;

            }

        }

    }

    return false;

}

inline int dinic(int u , int flow)

{

    int rest = flow;

    if (u == T)

        return flow;

    for (int i = head[u]; i && rest; i = e[i].nxt)

    {

        int v = e[i].to , w = e[i].w;

        if (w >  && dep[v] == dep[u] + )

        {

            int k = dinic(v , min(rest , w));

            if (!k) dep[v] = ;

            rest -= k;

            e[i].w -= k;

            e[i ^ ].w += k;

        }

    }

    return flow - rest;

}

int main()

{

    read(n); read(m);

    tot = ;

    S = n +  , T = S + ;

    for (int i = ; i <= n; i++)

    {

        int x;

        read(x);

        if (!x) addedge(S , i , );

        else addedge(i , T , );

    }

    for (int i = ; i <= m; i++)

    {

        int x , y;

        read(x); read(y);

        addedge(x , y , );

        addedge(y , x , );

    }

    int ans = ;

    while (bfs(S))

    {

        while (int flow = dinic(S , inf)) ans += flow;

    }

    printf("%d\n" , ans);

    return ;

}