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).
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.

def jam():
        while True:
                
                h1 = input()
                h2 = input()
                h1 = h1.split(':')
                h2 = h2.split(':')
                if h1[0] < '25' and h1[1] < '61' and h2[0] < '25' and h2[1] < '61':
                        break

        h10 = int(h1[0])
        h20 = int(h2[0])
        h11 = int(h1[1])
        h21 = int(h2[1])
                        
        


        if h10 - h20 < 0:
                h10 += 24
                hasil = h10-h20
        else:
                hasil = h10-h20
        
        
                
        if h11 - h21 < 0:
                h11 += 60
                hasil2 = h11-h21
                hasil -=1
        else:
                hasil2 = h11-h21
        if hasil < 10:
                hasil = str(hasil)
                hasil = '0'+hasil
                
        if hasil2 < 10:
                hasil2 = str(hasil2)
                hasil2 = '0'+hasil2
        hasil = str(hasil)
        hasil2 = str(hasil2)
        waktu = [hasil, hasil2]
        waktu =':'.join(waktu)
        print(waktu)


jam()

 	 			      		 	 				   		 	