OpenJudge1455 An Easy Problem

#include <cstdio>
#include <algorithm>
#include <cstring>
using namespace std;
int n;
int main()
{
int lowbit;
while(scanf("%d",&n)==1&n!=0)
{
lowbit=n&-n;
printf("%d\n",n+lowbit+(((n^(n+lowbit))/lowbit)>>2));
}
return 0;
}