#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <list>
#include <climits>
#include <string>
#include <stack>
#include <map>
#include <set>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <sstream>
#include <iomanip>

#define ALL(v) v.begin(), v.end()
#define REP(i, a, b) for(int i = a; i < b; i++)
#define REPD(i, a, b) for(int i = a; i > b; i--)
#define REPLL(i, a, b) for(ll i = a; i < b; i++)
#define FOR(i, a, b) for(int i = a; i <= b; i++)
#define FORD(i, a, b) for(int i = a; i >= b; i--)
#define FORLL(i, a, b) for(ll i = a; i <= b; i++)
#define INF 1000000001

#define vit vector<int>::iterator
#define sit set<int>::iterator
#define vi vector<int>
#define vpii vector<pii >

#define ll long long
#define ld long double

#define PB push_back
#define MP make_pair
#define pii pair<int, int>
#define pld pair<ld, ld>
#define st first
#define nd second

#define EPS 1e-9
#define PI acos(-1.0)
#define MAXN 10004
#define MAXM 10005

using namespace std;

int z, n, m, t, c;
vpii items;
ll amuse[MAXN];
int types[MAXM];

int main()
{
	cin >> z;
	FOR(tc, 1, z) {
        cin >> n >> m >> c;
        memset(types, 0, sizeof(types));
        memset(amuse, 0, sizeof(amuse));
        items.clear();
        REP(i, 0, n) {
            cin >> t;
            types[t]++;
        }
        FOR(i, 1, m) if(types[i]) {
            items.PB(MP(types[i], i));
        }
        sort(ALL(items));
        FORD(i, items.size()-1, 0) {
            amuse[i] = (i < n-1 ? amuse[i+1] : 0) + (items[i].nd*items[i].nd)%c;
        }
        int i = 0;
        ll ret = 0;
        FOR(h, 1, n) {
            while(i < items.size() && items[i].st < h) i++;
            if(i == items.size()) break;
            ret = max(ret, h*(amuse[i]));
        }
        cout << "Case " << tc << ": " << ret << endl;
	}

    return 0;
}