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}')