#include <bits/stdc++.h>

using namespace std;

char s[10];
int T, n, a[10], l, r, m, sum[1 << 10], cnt[1 << 10], b[1 << 10][1 << 10];
bool f[6][1 << 10];

bool check(int m) {
  memset(f, 0, sizeof(f));
  memset(cnt, 0, sizeof(cnt));
  for (int i = 0; i < 1 << 10; ++i) {
    f[0][i] = 1;
    for (int j = 0; j < 1 << 10; ++j)
      if (!(i & j) && n - sum[j] <= m)
        b[i][cnt[i]++] = j;
  }
  for (int i = 1; i <= 5; ++i)
    for (int j = 0; j < 1 << 10; ++j)
      for (int k = 0; k < cnt[j] && !f[i][j]; ++k)
          f[i][j] = f[i - 1][j | b[j][k]];
  for (int i = 0; i < 1 << 10; ++i)
    if (f[5][i])
      return 1;
  return 0;
}

int main() {
  scanf("%d", &T);
  while (T--) {
    scanf("%d", &n);
    memset(a, 0, sizeof(a));
    for (int i = 0; i < n; ++i) {
      scanf("%s", s);
      ++a[s[4] - '0'];
    }
    for (int i = 0; i < 1 << 10; ++i) {
      sum[i] = 0;
      for (int j = 0; j < 10; ++j)
        if (i & 1 << j)
          sum[i] += a[j];
    }
    l = 1;
    r = n;
    while (l < r) {
      m = (l + r) / 2;
      if (check(m))
        r = m; else
        l = m + 1;
    }
    printf("%d\n", l);
  }
  return 0;
}