#include <cstdio>

 #include <cstring>

 #include <algorithm>

 using namespace std;

 typedef long long ll;

 #define INF 0x7fffffff7fffffff

 #define clr(a,b) memset(a,b,sizeof(a))

 #define rep(i,s,t) for(int i=s;i<=t;i++)

 const int N = 1e5+;

 struct Edge{

     int to,nxt;

 }edge[N<<];

 int n,m,cnt,head[N];

 ll val[N],dp[N],ans,sum;

 ll llabs(ll a){return a>=?a:(-a);}

 void init(){

     cnt=;sum=;clr(head,-);

 }

 void addedge(int u,int v){

     edge[cnt].to=v,edge[cnt].nxt=head[u];

     head[u]=cnt++;

 }

 void dfs(int u,int pre){

     dp[u]=val[u];

     for(int i=head[u];~i;i=edge[i].nxt){

         int v = edge[i].to;

         if(v == pre)continue;

         dfs(v,u);

         dp[u]+=dp[v];

     }

     ans=min(ans,llabs(dp[u]-(sum-dp[u])));     //记录最小的差值

 }

 int main(){

     int ncase=;

     while(scanf("%d%d",&n,&m)!=EOF,n||m){

         init();

         rep(i,,n)scanf("%lld",&val[i]),sum+=val[i];

         rep(i,,m){

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

             addedge(u,v);addedge(v,u);

         }

         ans=INF;

         dfs(,-);

         printf("Case %d: %lld\n",++ncase,ans);

     }

 }