#include<iostream>

 #include<cstdio>

 #include<cstring>

 #include<cstdlib>

 #include<cmath>

 #include<climits>

 #include<algorithm>

 #include<stack>

 #include<map>

 #include<set>

 #include<vector>

 #include<queue>

 #include<list>

 using namespace std;

 #define MAXN 111111

 #define inf 1<<30

 #define INF 1LL<<60

 typedef long long ll;

 typedef pair<int,int>PP;

 template<class T> inline T Get_MIN(const T &a,const T &b){ return a < b ? a : b; }

 template<class T> inline T Get_MAX(const T &a,const T &b){ return a > b ? a : b; }

 template<class T> inline T ABS(const T &a){ return a <  ? -a : a; }

 struct Edge{

     int v,next;

 }edge[MAXN<<];

 int n,m,NE;

 int head[MAXN];

 void Insert(int u,int v)

 {

     edge[NE].v=v;

     edge[NE].next=head[u];

     head[u]=NE++;

 }

 ll dp[MAXN],sum,MIN;

 void dfs(int u,int father)

 {

     for(int i=head[u];i!=-;i=edge[i].next){

         int v=edge[i].v;

         if(v==father)continue;

         dfs(v,u);

         dp[u]+=dp[v];

     }

     MIN=Get_MIN(MIN,ABS((dp[u]-(sum-dp[u]))));

    // cout<<u<<"**"<<dp[u]<<"****"<<abs(sum-dp[u])<<"**"<<MIN<<endl;

 }

 int main()

 {

     int u,v,t=;

     while(~scanf("%d%d",&n,&m)&&(n||m)){

         NE=;

         memset(head,-,sizeof(head));

         sum=;

         for(int i=;i<=n;i++)scanf("%lld",&dp[i]),sum+=dp[i];

         while(m--){

             scanf("%d%d",&u,&v);

             Insert(u,v);

             Insert(v,u);

         }

         MIN=INF;

         dfs(,-);

         printf("Case %d: %lld\n",t++,MIN);

     }

     return ;

 }