백준 2292

#include <iostream>
using namespace std;
int getCount(int n)
{
	if (n == 1) return 1;
	int result = 1;int stage = 1;
	while (1) {
		result += 6 * stage;
		if (n <= result) break;
		stage++;
	}
	return stage+1;
}
int main() {
	int n;
	cin >> n;
	cout<<getCount(n);
}