#include<fstream.h>
int main()
{
	ifstream fcin("cmmdc.in");
	ofstream fcout("cmmdc.out");
	int a,b;
	fcin>>a>>b;
	while (a*b!=0)
		if (a>b)
			a=a%b;
		else
			b=b%a;
	if (a+b==1)
		fcout<<0<<"\n";
	else
		fcout<<a+b<<"\n";
	fcin.close();
	fcout.close();
	return 0;
}