SGU123――The sum（又见斐波那契） - c++编程基础

The Fibonacci sequence of numbers is known: F1 = 1; F2 = 1; Fn+1 = Fn + Fn-1, for n>1. You have to find S - the sum of the first K Fibonacci numbers.

Input

First line contains natural number K (0

Output

First line should contain number S.

Sample Input

Sample Output

斐波那契简单变种~水

#include  
#include




  
#include  
#include  
#include  
#include  
#include  
#include  
#include  
#include  
#include  
#include  
#include  
using namespace std;  
int a[50]= {0,1,1};  
int main()  
{  
    int n;  
    for(int i=2; i<50; i++)  
        a[i+1]=a[i]+a[i-1];  
    int s;  
    while(scanf("%d",&n)!=EOF)  
    {  
        s=0;  
        for(int i=0; i<=n; i++)  
            s+=a[i];  
        printf("%d\n",s);  
    }  
    return 0;  
}