s,v=map(int,input().split())
t=s/v+10
tz=(8*60)-t
h=int(tz/60)
if h>0:
    min=int(tz%60)
    if min>9:
        print(f"0{h}:{min}")
    else:
        print(f"0{h}:0{min}")
else:
    h=int(23+h)
    min = int(tz % 60)
    if min > 9:
        print(f"{h}:{min}")
    else:
        print(f"{h}:0{min}")