Sleepy Kaguya

版权声明：来自星空计算机团队(QQ群：134826825)——申屠志刚 https://blog.csdn.net/weixin_43272781/article/details/85936800

https://ac.nowcoder.com/acm/contest/338/C

题解：验算一下，发现其实只有1和-1两个答案。奇数为-1，偶数为1；

演算过程：

G(k)=F[k+1]*F[k+1]-F[k]*F[k+2]

=F[k+1]*F[k+1]-F[k]*(F[k]+F[k+1])

=(F[k+1]-F[k])*F[k+1]-F[k]*F[k]

=F[k-1]*F[k+1]-F[k]*F[k]

所以G(k)=-G(k-1)

参考文章：https://blog.csdn.net/weixin_43272781/article/details/82858423

/*
*@Author:   STZG
*@Language: C++
*/
#include <bits/stdc++.h>
#include<iostream>
#include<algorithm>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<string>
#include<vector>
#include<bitset>
#include<queue>
#include<deque>
#include<stack>
#include<cmath>
#include<list>
#include<map>
#include<set>
//#define DEBUG
#define RI register int
using namespace std;
typedef long long ll;
//typedef __int128 lll;
const int N=100000+10;
const int MOD=1e9+7;
const double PI = acos(-1.0);
const double EXP = 1E-8;
const int INF = 0x3f3f3f3f;
ll t,n,m,k,q,ans;
int a;
char str;
int main()
{
#ifdef DEBUG
	freopen("input.in", "r", stdin);
	//freopen("output.out", "w", stdout);
#endif
    scanf("%lld",&n);
    if(n%2==0){
        cout << 1 << endl;
    }else{
        cout << -1 << endl;
    }
    //cout << "Hello world!" << endl;
    return 0;
}