#include <bits/stdc++.h>
using namespace std;
vector<long long> graph[100005];
vector<pair<long long, long long> > graph_p[100005];
long long power(long long x, long long y) {
  long long res = 1;
  x = x % 1000000007;
  if (x == 0) return 0;
  while (y > 0) {
    if (y & 1) res = ((res % 1000000007) * (x % 1000000007)) % 1000000007;
    y = y >> 1;
    x = ((x % 1000000007) * (x % 1000000007)) % 1000000007;
  }
  return res;
}
void init_graph(long long n, long long m) {
  cin >> n >> m;
  for (long long i = 1; i <= m; i++) {
    long long a, b;
    cin >> a >> b;
    graph[a].push_back(b);
    graph[b].push_back(a);
  }
}
void sieve(long long n) {
  bool prime[n + 1];
  memset(prime, true, sizeof(prime));
  for (long long p = 2; p * p <= n; p++) {
    if (prime[p] == true) {
      for (long long i = p * p; i <= n; i += p) prime[i] = false;
    }
  }
}
long long gcd(long long a, long long b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
long long dp[1005][1005];
void reduce_to_zero() {
  long long range = 100, add = 0;
  long long x = 1;
  while (range) {
    add += min(range, x);
    x;
    range -= min(x, range);
  }
}
void we_have_choices() {
  long long n, k, mx = -1;
  cin >> n >> k;
  long long a[n + 1];
  for (long long i = 0; i < n; i++) cin >> a[i];
  long long pos = -1, sum = 0;
  for (long long i = 0; i < n; i++) {
    sum += a[i];
    if (sum % k) {
      pos = i;
      break;
    }
  }
  if (pos == -1) {
    cout << "-1";
    cout << "\n";
    return;
  } else {
    sum = 0;
    for (long long i = 0; i < n; i++) {
      sum += a[i];
      if (sum % k)
        mx = i + 1;
      else
        mx = max(mx, i - pos);
    }
    cout << mx;
    cout << "\n";
  }
}
int32_t main() {
  ios_base::sync_with_stdio(false), cin.tie(nullptr);
  ;
  long long t;
  cin >> t;
  while (t--) we_have_choices();
  return 0;
}
