保证AC

#include<bits/stdc++.h>
using namespace std;
const int N = 1e6 + 10;
const int NN = 1e3 + 10;
const int INF = 0x3f3f3f3f;
int n, a[N]; 
int main(){
	cin >> n;
	a[1] = 1;
	a[2] = 1;
	a[3] = 2;
	a[4] = 3;
	a[5] = 5;
	a[6] = 8;
	for (int i = 7; i <= n; i++){
		a[i] = a[i - 1] + a[i - 2];
    }
	cout << a[n];
}