HDU 1525 Euclid's Game

#include <stdio.h>
#include <iostream>

using namespace std;

int dfs(int a,int b,int ans)
{
    if(a%b==0)
    {
        return ans;
    }
    else if(a>b&&a<2*b)
    {
        return dfs(b,a%b,ans^1);
    }
    else
    {
        return ans;
    }
}

int main()
{
    int a,b;
    while(scanf("%d%d",&a,&b)!=EOF)
    {
        if(a==0&&b==0)
            break;
        
        if(a<b) swap(a,b);
        if(dfs(a,b,1)==1)
        {
            printf("Stan wins\n");
            
        }
        else
            printf("Ollie wins\n");
    }
}