#include<cstdio>

#include<algorithm>

#include<cstring>

using namespace std;

typedef long long ll;

const int maxn = 1e4+;

ll cnt[maxn];

ll r[maxn];

bool cmp(int a,int b) { return cnt[a] > cnt[b]; }

int main()

{

    int T;

    scanf("%d",&T);

    for(int k = ; k <= T; k++){

        int M,N,C;

        scanf("%d%d%d",&M,&N,&C);

        memset(cnt,,sizeof(cnt));

        for(int i = ; i < M; i++){

            int tmp;

            scanf("%d",&tmp);

            cnt[tmp]++;

        }

        for(int i = ; i < N; i++) { r[i]  = i+; }

        sort(r,r+N,cmp);

        ll amus = (r[]*r[])%C;

        ll best = cnt[r[]]*amus;

        for(int i = ; i < N; i++) {

            amus += (r[i]*r[i])%C;

            ll tmp = cnt[r[i]]*amus;

            best = max(best,tmp);

        }

        printf("Case %d: %I64d\n",k,best);

    }

    return ;

}