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

	return 0;
}

/**************************************************************
	Problem: 1307
	User: fuyijun
	Language: C++
	Result: Runtime Error
****************************************************************/