## Problem J4: Arrival Time

Fiona commutes to work each day. If there is no rush-hour traffic, her commute time is 2 hours. However, there is often rush-hour traffic. Specifically, rush-hour traffic occurs from 07:00 (7am) until 10:00 (10am) in the morning and 15:00 (3pm) until 19:00 (7pm) in the afternoon. During rush-hour traffic, her speed is reduced by half.

She leaves either on the hour (at XX:00), 20 minutes past the hour (at XX:20), or 40 minutes past the hour (at XX:40).

Given Fiona's departure time, at what time does she arrive at work?

### Input Format

The input will be one line, which contains an expression of the form `HH:MM`, where `HH` is one of the 24 starting hours (00, 01, …, 23) and `MM` is one of the three possible departure minute times (00, 20, 40).

### Output Format

Output the time of Fiona's arrival, in the form `HH:MM`.

```05:00
```

```07:00
```

### Explanation 1

Fiona does not encounter any rush-hour traffic, and leaving at 5am, she arrives at exactly 7am.

```07:00
```

```10:30
```

### Explanation 2

Fiona drives for 3 hours in rush-hour traffic, but only travels as far as she normally would after driving for 1.5 hours. During the final 30 minutes (0.5 hours) she is driving in non-rush-hour traffic.

```23:20
```

```01:20
```

### Explanation 3

Fiona leaves at 11:20pm, and with non-rush-hour traffic, it takes two hours to travel, so she arrives at 1:20am the next day.

Point Value: 5
Time Limit: 2.00s
Memory Limit: 16M
Added: Feb 22, 2016

Languages Allowed:
C++03, PAS, C, HASK, ASM, RUBY, PYTH2, JAVA, PHP, SCM, CAML, PERL, C#, C++11, PYTH3

• (0/0)
I don't get the explanation 2
 but only travels as far as she normally would after driving for 1.5 hours.

• (0/0)
Can someone plz help?

• (0/0)
For Explanation 2, it takes twice as long as non-rush-hour traffic, so 3 hours / 2 is 1.5 hours, aka when she travels for 3 hours in rush hour traffic, she only travels as far as she would when she travels 1.5 hours.
hope this helps :-)

• (0/0)
thx