s,v = map(int,input().split()) 
import math as m 
yh,ym = 8,0  
th,tm = m.ceil(s/v)//60,m.ceil(s/v)%60+10 
ph,pm = yh-th,ym-tm 

if pm < 0:   #退位
    ph -= 1
    pm += 60
if ph < 0:
    ph += 24
    
if ph < 10:
    print('0%d:' %(ph),end='')
elif ph >= 10:
    print('%d:' %(ph),end='')
if pm < 10:
    print('0%d' %(pm),end='')
elif pm >= 10:
    print('%d' %(pm),end='')

样例四和样例七过不去

求dalao指点