#include<iostream>
#include<sstream>
#include<cstdio>
#include<cstring>
#include<string>
#include<vector>
#include<list>
#include<queue>
#include<utility>
#include<set>
#include<map>
#include<cctype>
#include<cmath>
#include<algorithm>
using namespace std;

typedef long long ll;

ll gcd(ll a, ll b) {
	if (b == 0) return abs(a);
	else return gcd(b, a % b);
}
int main(){
int a,b;
cin >> a >> b;
cout << (gcd(a,b)) << endl;
return 0;
}