Latest Departure Time

yyy's home and the school are separated by a distance of \(s\) meters. yyy walks to school at a constant speed of \(v\) meters per minute. On the way, yyy also spends an extra 10 minutes for garbage sorting.

The school requires arrival by \(\textrm{8:00}\) AM. Calculate the latest time that yyy can depart from home without being late.

The travel time (in minutes) is determined by:

$$\text{travel time} = \lceil \frac{s}{v} \rceil$$

Thus, the departure time (in minutes) is computed as:

$$T = 480 - \left(\lceil \frac{s}{v} \rceil + 10\right)$$

Here, 480 minutes represents \(\textrm{8:00}\) AM. If \(T < 0\), add 1440 minutes to convert it to the corresponding time on the previous day. It is guaranteed that the departure time will not be earlier than one day before \(\textrm{8:00}\) AM.

inputFormat

The input consists of two space-separated integers, \(s\) and \(v\), where:

• \(s\) is the distance in meters between yyy's home and the school.
• \(v\) is yyy's walking speed in meters per minute.

It is guaranteed that the calculated departure time does not exceed one day before \(\textrm{8:00}\) AM.

outputFormat

Output the latest departure time in the 24-hour HH:MM format. Hours and minutes should each be padded with a leading zero if necessary.

sample

1000 50

07:30