1 #include "bits/stdc++.h"
2 using namespace std;
3 typedef long long LL;
4 const int MAX=305;
5 const int M=MAX*MAX;
6 int n,m,s,t;
7 int tot,head[MAX],adj[M],wei[M],next[M];
8 int deep[MAX],cur[MAX];
9 inline int read(){
10 int an=0,x=1;char c=getchar();
11 while (c<'0' || c>'9') {if (c=='-') x=-1;c=getchar();}
12 while (c>='0' && c<='9') {an=(an<<3)+(an<<1)+c-'0';c=getchar();}
13 return an*x;
14 }
15 void addedge(int u,int v,int w){
16 tot++;adj[tot]=v,wei[tot]=w,next[tot]=head[u],head[u]=tot;
17 }
18 bool bfs(){
19 int i,j,u;
20 memset(deep,127,sizeof(deep));
21 deep[s]=0;
22 queue <int> q;q.push(s);
23 while (!q.empty()){
24 u=q.front();q.pop();
25 for (i=head[u];i;i=next[i]){
26 if (deep[adj[i]]>1e9 && wei[i]>0)
27 deep[adj[i]]=deep[u]+1,q.push(adj[i]);
28 }
29 }
30 return deep[t]<1e9;
31 }
32 int dfs(int x,int flo){
33 if (x==t || flo==0) return flo;
34 int j;
35 for (int &i=cur[x];i;i=next[i]){
36 if (deep[adj[i]]==deep[x]+1 && wei[i]>0){
37 j=dfs(adj[i],min(flo,wei[i]));
38 if (j){
39 wei[i]-=j,wei[i^1]+=j;
40 return j;
41 }
42 }
43 }
44 return 0;
45 }
46 int main(){
47 freopen ("vote.in","r",stdin);freopen ("vote.out","w",stdout);
48 int i,j,u,v;
49 n=read(),m=read();tot=1;s=n+1,t=n+2;
50 for (i=1;i<=n;i++){
51 u=read();
52 if (u==1) addedge(s,i,1),addedge(i,s,0);
53 else addedge(i
54 ,t,1),addedge(t,i,0);
55 }
56 for (i=1;i<=m;i++){
57 u=read();v=read();
58 addedge(u,v,1),addedge(v,u,1);
59 }
60 int flow=0,dd;
61 while (bfs()){
62 for (i=1;i<=n+2;i++) cur[i]=head[i];
63 while (dd=dfs(s,1e9)) flow+=dd;
64 }
65 printf("%d",flow);
66 return 0;
67
