#include <iostream>
#include <string>
#include <cmath>

using namespace std;


int main(void){

	unsigned int n;
	cin >> n;
	int np = n / 3;
	int ans;
	ans = sqrt(np);
	int lans;
	lans = int(ans);
	if (lans == 0){
		lans = 1;
	}
	cout << lans << endl;
	return 0;
}