[백준-2292번/Java] 벌집

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int N = sc.nextInt();
		int honeyHouse = 1;
		int d = 6;
		int d_cnt = 1;
		while (true) {
			if (honeyHouse >= N)
				break;
			honeyHouse += d * d_cnt;
			d_cnt++;
		}

		System.out.println(d_cnt);

		sc.close();
	}

}