2292번 '벌집'

import Foundation
 
var input = Int(readLine()!)!
var count = 1
var row = 0
for _ in 0...1000000{
    var room = 0
    if(row == 0){
        room = 1
    }
    else{
        room = row*6
    }
    if(input - room > 0){
        input -= room
        count += 1
        row += 1
    }
    else{
        print(count)
        exit(0)
    }
}