#include <bits/stdc++.h>
using namespace std;
void eea(long long int a, long long int b, long long int &x, long long int &y) {
  if (a == 1) {
    x = 1;
    y = 0;
    return;
  }
  long long int x1, y1;
  eea(b % a, a, x1, y1);
  x = y1 - (b / a) * x1;
  y = x1;
}
long long int mi(long long int a, long long int m) {
  long long int x, y;
  eea(a, m, x, y);
  x = (x % m + m) % m;
  return x;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long int t = 1;
  cin >> t;
  while (t--) {
    int n, x;
    cin >> n >> x;
    int a[n], b, c = n, d, e = n;
    cin >> a[0];
    b = a[0];
    for (int i = 1; i < n; i++) {
      cin >> a[i];
      b = a[i] + b;
    }
    d = b;
    for (int i = 0; i < n; i++) {
      if (b % x != 0)
        break;
      else {
        c--;
        b = b - a[i];
      }
    }
    for (int i = n - 1; i >= 0; i--) {
      if (d % x != 0)
        break;
      else {
        e--;
        d = d - a[i];
      }
    }
    int m = max(c, e);
    if (m != 0)
      cout << m << "\n";
    else
      cout << -1 << "\n";
  }
}
