#include <bits/stdc++.h>
using namespace std;
int main(){
	long long a,b,r;//a是被除数，b是除数，r是余数
	cin>>a>>b;
	r=a%b;
	while (r!=0){
		a=b;
		b=r;
		r=a%b;
	}
	cout<<b<<endl;
	
}