#include <bits/stdc++.h>
using namespace std;
const long long m = 1e9 + 7;
long long power(long long x, long long y) {
  long long res = 1;
  x = x;
  while (y > 0) {
    if (y & 1) res = (res * x);
    y = y >> 1;
    x = (x * x);
  }
  return res;
}
long long logtwo(long long n) {
  if (n == 1) return 0;
  return logtwo(n / 2) + 1;
}
long long binV(vector<long long> arr, long long x) {
  long long l = 0;
  long long r = arr.size() - 1;
  while (l <= r) {
    long long m = l + (r - l) / 2;
    if (arr[m] == x) return m;
    if (arr[m] > x)
      r = m - 1;
    else
      l = m + 1;
  }
  return -1;
}
long long binA(long long arr[], long long l, long long r, long long x) {
  while (l <= r) {
    long long m = l + (r - l) / 2;
    if (arr[m] == x) return m;
    if (arr[m] > x)
      r = m - 1;
    else
      l = m + 1;
  }
  return -1;
}
vector<long long> primeV;
bool isPrime(long long x) {
  for (long long i = 0; i < primeV.size(); i++)
    if (x % primeV[i] == 0) return false;
  return true;
}
void makePrime() {
  primeV.push_back(2);
  for (long long i = 3; i <= 1001; i += 2) {
    if (isPrime(i)) primeV.push_back(i);
  }
}
struct customCompareForSet {
  bool operator()(const pair<long long, long long> &a,
                  const pair<long long, long long> &b) const {
    long long lena = a.second - a.first + 1;
    long long lenb = b.second - b.first + 1;
    if (lena == lenb) return a.first < b.first;
    return lena > lenb;
  }
};
vector<pair<long long, long long>> traverse_4 = {
    {1, 0}, {0, 1}, {-1, 0}, {0, -1}};
vector<pair<long long, long long>> traverse_8 = {
    {1, 0}, {0, 1}, {-1, 0}, {0, -1}, {1, 1}, {1, -1}, {-1, 1}, {-1, -1}};
bool checkWithinGrid(pair<long long, long long> pr, long long Rows,
                     long long Cols) {
  if (pr.first >= 0 && pr.first < Rows && pr.second >= 0 && pr.second < Cols)
    return true;
  return false;
}
signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long t;
  cin >> t;
  while (t--) {
    long long n, x;
    cin >> n >> x;
    long long arr[n];
    long long sum = 0;
    for (long long i = 0; i < n; i++) {
      cin >> arr[i];
      sum += arr[i];
    }
    if (sum % x != 0) {
      cout << n << "\n";
      continue;
    }
    long long st = -1;
    long long end = -1;
    for (long long i = 0; i < n; i++) {
      if (arr[i] % x != 0) {
        st = i + 1;
        break;
      }
    }
    for (long long i = n - 1; i >= 0; i--) {
      if (arr[i] % x != 0) {
        end = i - 1;
        break;
      }
    }
    if (st == -1 && end == -1) {
      cout << st << "\n";
      continue;
    }
    long long len_s = n - st;
    long long len_e = end + 1;
    cout << max(len_s, len_e) << "\n";
  }
}
