[백준] 2292번 벌집 풀이

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

cnt = 1
count = 1
cnt_six = 6
input = int(input())
if input == 1:
    print("1")
else:
    while input > cnt:
        count += 1
        cnt += cnt_six
        cnt_six += 6
    print(count)