#include <bits/stdc++.h>
using namespace std;

char buf[10];
int sum[20], sss[1 << 10];
int dp[10][1 << 10];

int dfs(int now, int mask) {
    if (now == 0) return 0;
    if (~dp[now][mask]) return dp[now][mask];
    int &res = dp[now][mask] = max(sss[(1 << 10) - 1], dfs(now - 1, mask));
    for (int mmm = mask; mmm; mmm = mmm - 1 & mask) {
        int maxj = max(sss[((1 << 10) - 1) ^ mmm], dfs(now - 1, mask ^ mmm));
        res = min(res, maxj);
    }
    return res;
}

int main () {
    int T; scanf("%d", &T);
    while (T--) {
        int n; scanf("%d", &n);
        memset(sum, 0, sizeof(sum));
        for (int i = 0; i < n; i++) {
            scanf("%s", buf);
            sum[buf[4] - '0']++;
        }
        for (int i = 1; i < (1 << 10); i++) {
            sss[i] = 0;
            for (int j = 0; j < 10; j++) {
                if (i >> j & 1) sss[i] += sum[j];
            }
        }
        memset(dp, -1, sizeof(dp));
        printf("%d\n", dfs(5, (1 << 10) - 1));
    }
    return 0;
}