#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>

typedef long long ll;

const ll mod=1e9+7;

const int dx[] = {0, 1, 0, -1};
const int dy[] = {1, 0, -1, 0};

#define all(x) x.begin(),x.end()
#define allr(x) x.rbegin(),x.rend()
#define rc(x)  return cout<<x<<"\n",0
#define sz(s)  (int) s.size()
#define pb push_back
#define mp make_pair
#define fr first
#define sc second

using namespace std;

ll t;

int euclid(int a, int b) {
	if (!b)return a;
	else return euclid(b,a%b);
}

int main() {
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
	ifstream cin("cmmdc.in");
	ofstream cout("cmmdc.out");
	ll a,b;
	cin >> a >> b;
	if (euclid(a,b)==1) {
		cout << "0\n";
	}
	else cout << euclid(a,b)<< '\n';

}