aaaicu

문제 : https://www.acmicpc.net/problem/2292 

 import java.util.Scanner;

public class Main {
    public static void main(String[] args) {

        Scanner scan = new Scanner(System.in);
        int input = scan.nextInt();
        int dist = 1;
        int count = 0;
        
        for(int i = 0 ; i < input ; i++) {
            if (i == dist) {
                count++;
                dist = dist + 6* count;     
            }
        }
        System.out.println(count+1);
    } 
    
}