蟠桃記

PRoblem Description

Input

Output

Example Input

240
Example Output
422
Answer:
#include<stdio.h>int f(int n){    if(n==1)        return 1;    else    return (f(n-1)+1)*2;}int main(){    int n;    while(~scanf("%d",&n)&&n)    {        printf("%d/n",f(n));    }    return 0;}