#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int> VI;
typedef vector<VI> VVI;
#define REP(i, n)           for(int(i)=0;(i)<(n);++(i))
#define FOR(i, f, t)        for(int(i)=(f);(i)<(t);(++i))
const int MOD = int(1e9+7);

ll gcd(ll n, ll m){return m?gcd(m,n%m):n;}

int main(){
    int N, M;
    cin >> N >> M;
    cout << gcd(N,M) << endl;
    return 0;
}