# include<iostream>

# include<cstdio>

# include<algorithm>

# include<cstring>

# include<cmath>

# include<queue>

using namespace std;

const int inf = 0x3f3f3f3f;

const int mn = ;

int head[mn],edge_max=;

struct edge{int to,next,flow;

};

edge e[mn*mn*];

int n,m;

void add_edge(int x,int y,int z)

{

    e[++edge_max].to=y;

    e[edge_max].next=head[x];

    e[edge_max].flow=z;

    head[x]=edge_max;

}

void add(int x,int y,int z)

{

   add_edge(x,y,z);

   add_edge(y,x,);

}

queue<int> q;

int deep[mn];

bool bfs(int x,int y)

{

    memset(deep,,sizeof(deep));

    q.push(x);

    deep[x]=;

    while(!q.empty())

    {

        int u=q.front();

        q.pop();

        for(int i=head[u];i;i=e[i].next)

        {

            if(e[i].flow> && deep[e[i].to]==)

            {

                deep[e[i].to]=deep[u]+;

                q.push(e[i].to);

            }

        }

    }

    return deep[y]!=;

}

int dfs(int x,int cost,int y)

{

    if(x==y) return cost;

    for(int i=head[x];i;i=e[i].next)

    {

        if(deep[e[i].to]==deep[x]+ && e[i].flow>)

        {

            int di=dfs(e[i].to,min(cost,e[i].flow),y);

            if(di>)

            {

                e[i].flow-=di;

                e[i^].flow+=di;

                return di;

            }

        }

    }

    return ;

}

int dinic(int x,int y)

{

    int ans=;

    while(bfs(x,y))

    {

    //    printf("ssss\n");

        while(int k=dfs(x,inf,y))

          ans+=k;

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

    }

    return ans;

}

int main()

{

    int st,en,x,y;

    scanf("%d%d",&n,&m);

    st=n+,en=n+;

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

    {

       scanf("%d",&x);

       if(x) {

       add(st,i,);

       //printf("%d %d\n",st,i);

       }

       else add(i,en,);

    }

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

    {

        scanf("%d%d",&x,&y);

        add(x,y,),add(y,x,);

    }

    printf("%d",dinic(st,en));

    return ;

}