题目描述

blablabla

样例

#include <bits/stdc++.h>
using namespace std;
int a[20],n;
int main()
{
    a[1] = 1;
    a[2] = 2;
    for (int i=3;i<=15;i++) 
        a[i]=a[i - 1]+a[i - 2];
    scanf("%d",&n);
    printf("%d\n",a[n]);
    return 0;
}