辗转相减(

_{辗转相减求最大公约数}(

# include <bits/stdc++.h>
typedef unsigned long long ull;

using  namespace  std ;
int i,j,k;
int p(int a,int b){
    if(a==b) return a;
    if(a>b) return p(a-b,b);
    else return p(a,b-a);
}
int  main ( )
{
    int a,b;
    cin>>a>>b;
    cout<<p(a,b);
    return  0 ;
}