5.1.2

#include <iostream>
#include <cmath>

using namespace std;

int main()
{
    int a,b,temp;
    cin>>a>>b;
    for(;b;)
    {
            a=a%b;
            temp=a;
            a=b;
            b=temp;
    }
    cout<<a;
    return 0;
}