#include<iostream>
#include<stdio.h>
#include<algorithm>
#include<vector>
#include<string.h>
#include<math.h>
#include<map>
#include<iomanip>
#include<queue>

using namespace std;

int main(){
	long long n;
	cin >> n;
	for(long long b=1;b<=n;b++){
		long long x=n+b*b;
		long long xx=sqrt(x);
		if(xx*xx==x){
			cout << 1 << endl;
			return 0;
		}
	}
	cout << -1 << endl;
	return 0;
}