#if 1
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <queue>
#include <stack>
#include <array>
#include <deque>
#include <algorithm>
#include <utility>
#include <cstdint>
#include <functional>
#include <iomanip>
#include <numeric>
#include <assert.h>
#include <complex>
int main() {
	int64_t n;
	std::string s;
	std::getline(std::cin, s);
	assert(std::all_of(s.begin(), s.end(), [](char c) {return '0' <= c && c <= '9'; }));
	n = std::stoll(s);
	std::cout << (int64_t)(sqrt(n*1.0 / 3) +1) << std::endl;
}
#endif