#include <bits/stdc++.h>
using namespace std;
const long long inf = 1e18 + 18;
const int oo = 1e9 + 9;
const int max6 = 1e6 + 6;
const int max5 = 1e5 + 5;
const int mod = 1e9 + 7;
int a[max5];
int main() {
  ios_base::sync_with_stdio(false);
  int t;
  cin >> t;
  while (t--) {
    int n, x;
    cin >> n >> x;
    int s = 0;
    for (int i = 1; i <= n; i++) cin >> a[i], s = s + a[i];
    if (s % x != 0) {
      cout << n << "\n";
      continue;
    } else {
      int l = 0, r = 0;
      int tmp = s;
      for (int i = 1; i <= n; i++) {
        tmp = tmp - a[i];
        if (tmp % x == 0) continue;
        l = n - i;
        break;
      }
      tmp = s;
      for (int i = n; i >= 1; i--) {
        tmp = tmp - a[i];
        if (tmp % x == 0) continue;
        r = i - 1;
        break;
      }
      if (l > 0 && r > 0) {
        if (l >= r) {
          cout << l << "\n";
          cerr << "l";
          continue;
        } else {
          cout << r << "\n";
          cerr << "r";
          continue;
        }
      }
    }
    cout << -1 << "\n";
  }
}
