#include <bits/stdc++.h>
using namespace std;
long long minn=0x3f3f3f3f;
int main()
{
	long long k;
	cin>>k;
	for(long long i=1;i*i<=abs(k);i++){
		if(k%i==0){
			if(abs(i+k/i)%2==0){
				long long m=(i+k/i)/2;
				long long n=k/i-m;
				minn=min(minn,n);
			}	
		} 
	} 
	if(k==0){
		cout<<0;
		return 0;
	}
	else if(minn==0x3f3f3f3f){
		cout<<"none";
		return 0;
	}
	else if((long long)(sqrt(k+minn*minn))*(long long)(sqrt(k+minn*minn))==k+minn*minn){
		cout<<(long long)(sqrt(k+minn*minn));
	}
	return 0;
}