#include <bits/stdc++.h>
using namespace std;
int read() {
  int s = 0;
  char c = getchar(), lc = '+';
  while (c < '0' || '9' < c) lc = c, c = getchar();
  while ('0' <= c && c <= '9') s = s * 10 + c - '0', c = getchar();
  return lc == '-' ? -s : s;
}
void write(int x) {
  if (x < 0) {
    putchar('-');
    x = -x;
  }
  if (x < 10)
    putchar(x + '0');
  else {
    write(x / 10);
    putchar(x % 10 + '0');
  }
}
void print(int x, char c = '\n') {
  write(x);
  putchar(c);
}
int gcd(int x, int y) { return y == 0 ? x : gcd(y, x % y); }
signed main() {
  int n = read(), k = read(), g = k;
  for (int i = 1; i <= n; i++) g = gcd(read() % k, g);
  print(k / g);
  for (int i = 0; i * g < k; i++) print(i * g, ' ');
  return 0;
}
