#include <cstdio>

#include <cstring>

#include <cmath>

#include <iostream>

#include <algorithm>

#include <queue>

#include <cstdlib>

#include <stack>

#include <vector>

#include <set>

#include <map>

#define LL long long

#define mod 1000000007

#define inf 0x3f3f3f3f

#define N 100010

#define clr(a) (memset(a,0,sizeof(a)))

using namespace std;

struct edge

{

    int next,v;

    edge(){}

    edge(int v,int next):v(v),next(next){}

}e[N*];

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

LL ans,sum,num[N];

LL Abs(LL a)

{

    return a>?a:-a;

}

void addedge(int u,int v)

{

    e[tot]=edge(v,head[u]);

    head[u]=tot++;

}

void dfs(int u,int fa)

{

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

    {

        int v=e[i].v;

        if(v==fa)continue;

        dfs(v,u);

        num[u]+=num[v];

    }

    ans=min(ans,Abs(sum-*num[u]));

}

int main()

{

    int u,v,cas=;

    while(scanf("%d%d",&n,&m)>)

    {

        if(n==&&m==)break;

        tot=;

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

        sum=;

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

            scanf("%lld",&num[i]),sum+=num[i];

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

        {

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

            addedge(u,v);

            addedge(v,u);

        }

       ans=1LL<<;

       dfs(,-);

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

    }

}