//minamoto

 #include<iostream>

 #include<cstdio>

 #include<cstring>

 #include<queue>

 #define inf 0x3f3f3f3f

 using namespace std;

 #define getc() (p1==p2&&(p2=(p1=buf)+fread(buf,1,1<<21,stdin),p1==p2)?EOF:*p1++)

 char buf[<<],*p1=buf,*p2=buf;

 inline int read(){

     #define num ch-'0'

     char ch;bool flag=;int res;

     while(!isdigit(ch=getc()))

     (ch=='-')&&(flag=true);

     for(res=num;isdigit(ch=getc());res=res*+num);

     (flag)&&(res=-res);

     #undef num

     return res;

 }

 const int N=,M=;

 int head[N],Next[M],ver[M],edge[M],tot=;

 int S,T,dep[N],cur[N],n,m;

 queue<int> q;

 inline void add(int u,int v,int e){

     ver[++tot]=v,Next[tot]=head[u],head[u]=tot,edge[tot]=e;

     ver[++tot]=u,Next[tot]=head[v],head[v]=tot,edge[tot]=;

 }

 bool bfs(){

     memset(dep,-,sizeof(dep));

     while(!q.empty()) q.pop();

     for(int i=S;i<=T;++i) cur[i]=head[i];

     q.push(S),dep[S]=;

     while(!q.empty()){

         int u=q.front();q.pop();

         for(int i=head[u];i;i=Next[i]){

             int v=ver[i];

             if(dep[v]<&&edge[i]){

                 dep[v]=dep[u]+,q.push(v);

                 if(v==T) return true;

             }

         }

     }

     return false;

 }

 int dfs(int u,int limit){

     if(u==T||!limit) return limit;

     int flow=,f;

     for(int i=cur[u];i;cur[u]=i=Next[i]){

         int v=ver[i];

         if(dep[v]==dep[u]+&&(f=dfs(v,min(limit,edge[i])))){

             flow+=f,limit-=f;

             edge[i]-=f,edge[i^]+=f;

             if(!limit) break;

         }

     }

     if(!flow) dep[u]=-;

     return flow;

 }

 int dinic(){

     int flow=;

     while(bfs()) flow+=dfs(S,inf);

     return flow;

 }

 int main(){

     //freopen("testdata.in","r",stdin);

     n=read(),m=read(),S=,T=n+;

     for(int i=,k;i<=n;++i) k=read(),k&?add(S,i,):add(i,T,);

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

         int u=read(),v=read();add(u,v,),add(v,u,);

     }

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

     return ;

 }