题解 | #统计每个月兔子的总数#

#include<iostream>
#include<cmath>
#include<algorithm>
#include <ostream>
using namespace std;

int main(){
    int n;
    long  ans;
    while(cin >> n){
        double  sqrt5 = sqrt(5);
        double  fibN = pow((1 + sqrt5) / 2, n) - pow((1 - sqrt5) / 2, n);
        ans = round(fibN / sqrt5);
        cout << ans  << endl;
    }
    return 0;
}