#include<iostream.h>
#include<fstream.h>
long a,b,c;
fstream f("cmmdc.in", ios::in);
fstream g("cmmdc.out", ios::out);
int main ()
{
 f>>a; f>>b;
 f.close();
 c=a%b;
 while (c!=0)
 {
  a=b;
  b=c;
  c=a%b;
  }
 if (b==1)
	g<<"0";
  else g<<b;
 g.close();
 return 0;
}