#include <cstdio>
#include <map>
#include <algorithm>
using namespace std;

typedef long long ll;

const int mod = 1000000007;

int t;
int n;
map <int, int> M;
int res;

int toPower(int a, int p)
{
    int r = 1;
    while (p) {
        if (p & 1) r = ll(r) * ll(a) % ll(mod);
        p >>= 1; a = ll(a) * ll(a) % ll(mod);
    }
    return r;
}

int main()
{
    scanf("%d", &t);
    for (int tc = 1; tc <= t; tc++) {
        M.clear();
        scanf("%d", &n);
        while (n--) {
            int a; scanf("%d", &a);
            M[a]++;
        }
        res = 0;
        for (map <int, int>::iterator it = M.begin(); it != M.end(); it++) if (it->second) {
            int inv = toPower(it->first, mod - 2);
            int lft = it->first == inv? it->second / 2: M.count(inv)? M[inv]: 0;
            if (!lft) continue;
            int tk = min(it->second, lft);
            it->second -= tk; M[inv] -= tk; res += tk;
        }
        printf("Case #%d: %d\n", tc, res);
    }
    return 0;
}