#include<iostream>
#include<cmath>
using namespace std;
void swap(int & a, int & b)
{
int c = a;
a = b;
b = c;
}
//计算a,b的最大公约数的函数gcd(int a,int b)
int gcd(int a,int b)
{
if(0 == a )
{
return b;
}
if( 0 == b)
{
return a;
}
if(a > b)
{
swap(a,b);
}
int c;
for(c = a % b ; c > 0 ; c = a % b)
{
a = b;
b = c;
}
return b;
}
int main()
{
int a, b;
cin >> a >> b;
cout << gcd(a,b);
system("PAUSE");
return 0;
}