func_code_string: #include <bits/stdc++.h>   using namespace std;   const long long MOD = 1e9 + 7;   const double EPS = 1e-9;   const long long INF = 1e18 + 2007;   const double PI = 3.1415926535897932384626433832795;   const long long N = 200005;   long long gcd(long long a, long long b) { return a ? gcd(b % a, a) : b; }   signed main() {     ios_base::sync_with_stdio(0);     long long n, k;     cin >> n >> k;     long long g = 0;     for (long long i = 0; i < n; i++) {       long long a;       cin >> a;       g = gcd(g, a);     }     set<long long> ans;     for (long long i = 0; i < k; i++) {       ans.insert((g * i) % k);     }     cout << ans.size() << endl;     for (auto x : ans) {       cout << x <<    ;     }     return 0;   }   