ZOJ 2417-Lowest Bit

#include<stdio.h>
int num[7]={1,3,7,15,31,63,127};
int main()
{
int n,i,t;
while(scanf("%d",&n)&&n!=0)
{
for(i=0;(n&num[i])==0;i++);
printf("%d\n",n&num[i]);
}
return 0;
}