#include <iostream>
using namespace std;
void maxCommonDivisor(int a,int b);
int main ()
{
int a,b;
cin >> a >> b ;
maxCommonDivisor(a,b);
return 0;
}
//运用辗转相除法
void maxCommonDivisor(int a,int b)
{
int t,c;
if (a<b)
{
t=a;
a=b;
b=t;
}
c=a-b;
if (a%c==0&&b%c==0)
cout <<c << endl ;
else
{
a=b;
b=c;
maxCommonDivisor(a,b);
}
}