#include<iostream>
#include<conio.h>
using namespace std;
int gcd(int a , int b)
{
if(b==0)
return a;
else
return gcd(b,a%b);
}
int main()
{
int x , y;
GET:cout<<"Enter two numbers:"<<endl;
cin>>x>>y;
if(!(x>0 && y>0))
{
cout<<"You must enter two natural numbers"<<endl;
goto GET;
}
cout<<"Gcd for "<<x<<" and "<<y<<" is "<<gcd(x,y)<<endl;
getch();
return 0;
}