a267: 太空梭的油箱

http://zerojudge.tw/ShowProblem?problemid=a267

• def every_month():
•     global N, fuel, month
•     fuel -= N+1
•     month += 1
•     N = int(fuel/5)-1 if fuel%5==0 else int(fuel/5)
•     if fuel==0:
•         return ’Mid2 94 Mid2’
•     every_month()
•  
• while True:
•     N = int(input())
•     if N == -1:
•         break
•     fuel = (N+1)*5
•     month = 0
•     every_month()
•     print(month)