#include <bits/stdc++.h>
using namespace std;
long long int power(long long int a, long long int b) {
  if (b == 0) return 1;
  if (b == 1) return a;
  long long int r = power(a, b / 2) % 1000000007;
  if (b % 2 == 0)
    return (r * r) % 1000000007;
  else
    return (((r * r) % 1000000007) * a) % 1000000007;
}
int prime[1000009];
int sumprime[1000009];
void sieve(int n) {
  prime[0] = prime[1] = 1;
  for (int i = 2; i <= sqrt(n); i++) {
    if (!prime[i]) {
      for (int j = 2 * i; j <= n; j = j + i) {
        prime[j]++;
      }
    }
  }
  for (int i = 1; i <= n; i++) {
    if (!prime[i]) {
      sumprime[i] = sumprime[i - 1] + 1;
    } else {
      sumprime[i] = sumprime[i - 1];
    }
  }
}
bool comp(const pair<long long int, long long int> &a,
          const pair<long long int, long long int> &b) {
  return (a.second < b.second);
}
const int N = 5 * 1e5 + 9;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int t;
  cin >> t;
  while (t--) {
    long long int n, x;
    cin >> n >> x;
    long long int a[n], sum = 0;
    ;
    for (int i = 0; i < n; i++) {
      cin >> a[i];
      sum += a[i];
    }
    long long int s = 0;
    long long int ma = -1;
    for (long long int i = 0; i < n; i++) {
      s += a[i];
      if (s % x != 0) {
        ma = max(ma, i + 1);
      }
      if (s % x != sum % x) {
        ma = max(ma, n - 1 - i);
      }
    }
    cout << ma << "\n";
  }
  return 0;
}
