When calculating electricity bills, the hourly rate is based off of the time of day. During "on peak" hours, the hourly rate is higher then during "off peak" hours. Given a number, determine if it is a valid hour of the day (using 24 hour time) and if it is, determine if it is on peak or off peak. On peak hours are between and including 9 and 17 (5pm) o'clock. Off peak hours are any other time of day. Numbers greater then 24 are not valid times of day.

Input Specification

The only line of input is ~n~ ~(1 \le n \le 10^6)~ representing the hour of day.

Output Specification

If the input is a valid hour, print on peak or off peak respective to the time of day. Otherwise, if it is not a valid time, print invalid.

Sample Input 1

12

Sample Output 1

on peak

Sample Input 2

25

Sample Output 2

invalid