CF387A.George and Sleep

George woke up and saw the current time s on the digital clock. Besides, George knows that he has slept for time t.

Help George! Write a program that will, given time s and t, determine the time p when George went to bed. Note that George could have gone to bed yesterday relatively to the current time (see the second test sample).

乔治醒来，看到数字钟上显示的当前时间为 $s$。此外，乔治知道他睡了 $t$ 长时间。

请帮助乔治！编写一个程序，在给定时间 $s$ 和 $t$ 的情况下，计算出乔治入睡的时间 $p$。注意：相对于当前时间，乔治可能是在昨天入睡的（参见第二个测试样例）。

The first line contains current time s as a string in the format "hh:mm". The second line contains time t in the format "hh:mm" — the duration of George's sleep. It is guaranteed that the input contains the correct time in the 24-hour format, that is, 00 ≤ hh ≤ 23, 00 ≤ mm ≤ 59.

第一行包含当前时间 $s$，格式为字符串 "hh:mm"。
第二行包含时间 $t$，格式为 "hh:mm" —— 表示乔治的睡眠时长。
保证输入的时间符合 24 小时制格式，即 $00 \leq hh \leq 23$，$00 \leq mm \leq 59$。

In the single line print time p — the time George went to bed in the format similar to the format of the time in the input.

在单行中输出时间 p —— 乔治睡觉的时间，格式与输入中的时间格式相同。

In the first sample George went to bed at "00:06". Note that you should print the time only in the format "00:06". That's why answers "0:06", "00:6" and others will be considered incorrect.

In the second sample, George went to bed yesterday.

In the third sample, George didn't do to bed at all.

在第一个样例中，乔治于“00:06”上床睡觉。注意，你只需按“00:06”这一格式输出时间。因此，“0:06”、“00:6”等其他格式的答案均被视为错误。

在第二个样例中，乔治是昨天上床睡觉的。

在第三个样例中，乔治根本没有上床睡觉。