#include <bits/stdc++.h>
using namespace std;
const int maxN = (int)1e6, maxM = (int)2e3, intMax = INT_MAX,
          maxValue = (int)1e4, intInf = (int)1e9, mod = (int)1e9, www = 97;
const long long llmax = LLONG_MAX, INF = (long long)1e9 + 1;
long long nod(long long a, long long b) {
  while (a != 0 && b != 0) {
    if (a < b)
      b %= a;
    else
      a %= b;
  }
  return a + b;
}
int nod(int a, int b) {
  while (a != 0 && b != 0) {
    if (a < b)
      b %= a;
    else
      a %= b;
  }
  return a + b;
}
long long nok(long long a, long long b) { return a * b / nod(a, b); }
int nok(int a, int b) { return a * b / nod(a, b); }
long long modPlus(long long a, long long b) {
  return ((a % mod) + (b % mod)) % mod;
}
int modPlus(int a, int b) { return ((a % mod) + (b % mod)) % mod; }
long long binPow(long long a, long long b) {
  long long res = 1;
  while (b) {
    if (b % 2 == 1) res = (res * a) % mod;
    a = (a * a) % mod;
    b >>= 1;
  }
  return res;
}
double binPow(double a, long long b) {
  double res = 1;
  while (b) {
    if (b % 2 == 1) {
      res *= a;
      while (res >= mod) res -= mod;
    }
    a *= a;
    while (a >= mod) a -= mod;
    b >>= 1;
  }
  return res;
}
long long mulmod(long long a, long long b) {
  long long res = 0;
  a = a % mod;
  while (b > 0) {
    if (b % 2 == 1) res = (res + a) % mod;
    a = (a * 2) % mod;
    b /= 2;
  }
  return res % mod;
}
pair<int, int> max(pair<int, int> a, pair<int, int> b) {
  if (a.first > b.first) return a;
  if (a.first < b.first) return b;
  if (a.second > b.second) return a;
  return b;
}
pair<int, int> min(pair<int, int> a, pair<int, int> b) {
  if (a.first < b.first) return a;
  if (a.first != b.first) return b;
  if (a.second < b.second) return a;
  return b;
}
int n, k, gcd, a;
vector<bool> Q;
int main() {
  scanf("%d%d", &n, &k);
  scanf("%d", &gcd);
  for (int i = 1; i < n; ++i) {
    scanf("%d", &a);
    gcd = nod(gcd, a);
  }
  printf("%d\n", k / nod(k, gcd));
  fflush(stdout);
  Q.resize(k);
  int act = gcd % k;
  while (!Q[act]) {
    Q[act] = 1;
    act = (act + gcd) % k;
  }
  for (int i = 0; i < k; ++i)
    if (Q[i]) printf("%d ", i);
  return 0;
}
