#include <fstream>
std::ifstream in("cmmdc.in");
std::ofstream out("cmmdc.out");
int main ()
{
	long a,b,c;
	in>>a>>b;
	while(a!=b)
	{
		if(a>b)
			a=a-b;
		else
			b=b-a;
	}
	if(a!=1)
	out<<a;
	else
		out<<0;
	in.close ();
	out.close ();
	return 0;
}