C++ :

#include<bits/stdc++.h>
using namespace std;
int a,b;
int main()
{
    //freopen("1045.in","r",stdin);
	//freopen("1045.out","w",stdout);
    cin>>a>>b;
    if(a>b){swap(a,b);}
    for(int i=a; ;i--)
	{
		if(a%i==0&&b%i==0)
		{
			cout<<i;
			break;
		}
		
	} 

    return 0;
}