a = input().split(' ')   
s,v = int(a[0]),int(a[1])
if s % v == 0:
    m = s // v + 10
else:
    m = s // v + 11 #多出的如1.01min,就要加多一分钟
h = m // 60
m = m % 60  #求余得到多的分钟

if h>=8:
    h1 = 31 - h 
    m1 = 60 - m
else:
    h1 = 7 - h 
    m1 = 60- m

if m1 == 60:
    h1 = h1 + 1
    m1 = 0
if h1 == 24:
    h1 = 0
print('%02d:%02d'%(h1,m1))