#define _USE_MATH_DEFINES
#include <algorithm>
#include <cstdio>
#include <functional>
#include <iostream>
#include <cfloat>
#include <climits>
#include <cstring>
#include <cmath>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <time.h>
#include <vector>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<ll, int> ll_i;
typedef pair<double, int> d_i;
typedef pair<ll, ll> ll_ll;
typedef pair<double, double> d_d;
struct edge { int u, v; ll w; };

ll MOD = 1000000007;
ll _MOD = 1000000009;
double EPS = 1e-10;

int main() {
    vector<vector<int> > d(100001);
    for (int i = 1; i <= 100000; i++)
        for (int j = 1; j * j <= i; j++)
            if (i % j == 0) {
                d[i].push_back(j);
                if (j * j != i)
                    d[i].push_back(i / j);
            }
    int T; cin >> T;
    for (int t = 1; t <= T; t++) {
        int n; cin >> n;
        vector<int> b(100001);
        while (n--) {
            int a; scanf("%d", &a);
            b[a]++;
        }
        vector<int> c(100001);
        for (int i = 1; i <= 100000; i++)
            if (b[i])
                for (int k = 0; k < d[i].size(); k++)
                    c[d[i][k]] += b[i];
        int i;
        for (i = 100000; c[i] <= 1; i--);
        printf("Case #%d: %d\n", t, i);
    }
}