题目:B4025

#include<bits/stdc++.h>
using namespace std;
long long noip, csp;
long long chenzheakioi(long long kkksc03, long long ioi) {
	if (ioi == 0) {
		return kkksc03;
	}
	return chenzheakioi(ioi, kkksc03 % ioi);
}
int main() {
	cin >>noip>>csp;
	cout << chenzheakioi(noip, csp);
	return 0;
}