백준 2292 c++

#include <iostream>

using namespace std;

int main(void)
{
	int N, temp = 1;
	int min = 0;

	cin >> N;
	if (N >= 1 && N <= 1000000000)
	{
		while (1)
		{
			temp = temp + (6 * min);
			if (temp < N)
			{
				min++;
			}
			else// (temp >= N)
			{
				break;
			}
		}
		min = min + 1;
		cout << min << endl;
	}
	else
	{
		;
	}
	return 0;
}

/*
* 2~7 : 5 = 6 * 1 - 1 
* 8~19 : 11 = 6 * 2 -1 
* 20~37 : 17 = 6 * 3 - 1 
* 38~61 : 23 = 6 * 4 - 1 
* 62~91: 29 = 6 * 5  - 1 
* .....
*/