#include<fstream.h>
int main()
	{
	int a,b,aux;
	ifstream f("cmmdc.in");
	ofstream g("cmmdc.out");
	f>>a>>b;

	while(a%b)
		{
		aux=a%b;
		a=b;
		b=aux;
		}
	if(b!=1)g<<b;
	else g<<0;
	return 0;
	}