s,v = map(int,input().split()) a = 8 t = s/v +10 if t == 60*(t//60): h,m = a-int(t//60), 0 else : h = a-(int(t//60) + 1) if t - int(t) != 0 : m = 60-(int(t-60*(t//60))+1) else : m = 60-int(t-60*(t//60)) if h < 0 : h = 24 + h if h < 10 : h = '0'+str(h) if m < 10 : m = '0'+str(m) print(f'{h}:{m}')