Java - 백준 코딩테스트 2292번 [기본수학1단계 - 벌집]

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
 
public class Honeycomb {
 
    public static void main(String[] args) throws IOException {
        // 20210722 - 백준 2292번
 
        int count = 1;
        int range = 2;
 
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int num = Integer.parseInt(br.readLine());
 
        if (num == 1) {
            System.out.println(1);
        } else {
            while (range <= num) {
                range += 6 * count;
                count++;
            }
            System.out.println(count);
        }
    }
}