#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <deque>
#include <algorithm>
#include <utility>
#include <stdint.h>
#include <string.h>
#include <functional>
#include <iomanip>
#include <numeric>
#include <string>
int main()
{
	int64_t N;
	std::cin >> N;
	for (int64_t i = 1; i <= 2000000; ++i)
	{
		if (i*i*3 >= N) {
			std::cout << i << std::endl;
			return 0;
		}
	}
}