# include<iostream>

# include<cstdio>

# include<cstring>

# include<algorithm>

using namespace std;

const int INF=1<<30;

int dp[10005][505];

int K[10005][505];

int a[10005];

int n,m;

void read()

{

    scanf("%d%d",&n,&m);

    for(int i=1;i<=n;++i)

        scanf("%d",a+i);

}

int solve()

{

    sort(a+1,a+n+1);

    for(int i=1;i<=n;++i){

        dp[1][i]=(a[i]-a[1])*(a[i]-a[1]);

        K[1][i]=0;

        if(i<=m){

            dp[i][i]=0;

            K[i][i]=i;

        }

    }

    for(int i=2;i<=m;++i){

        K[i][n+1]=n;

        for(int j=n;j>=i;--j){

            dp[i][j]=INF;

            for(int k=K[i-1][j];k<=K[i][j+1];++k){

                if(dp[i][j]>dp[i-1][k-1]+(a[j]-a[k])*(a[j]-a[k])){

                    dp[i][j]=dp[i-1][k-1]+(a[j]-a[k])*(a[j]-a[k]);

                    K[i][j]=k;

                }

            }

        }

    }

    return dp[m][n];

}

int main()

{

    int T,cas=0;

    scanf("%d",&T);

    while(T--)

    {

        read();

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

    }

    return 0;

}