hdu2018

http://acm.hdu.edu.cn/showproblem.php?pid=2018

 #include<iostream>
 #include<stdio.h>
 #include<math.h>
 #include<string.h>
 #include<stdlib.h>
 using namespace std;

 int main()
 {
     int f[];
     memset(f,,sizeof(f));
     f[]=;f[]=;f[]=;f[]=;
     for(int i=;i<;i++)
     {
         f[i]=f[i-]+f[i-];
     }
     int n;
     while(cin>>n)
     {
         if(n==)
         break;
         printf("%d\n",f[n]);
     }
     return ;
 }