s,v = map(float,input().split())
t = s/v+10
h = round(t//60)
if t%1 > 0 :
    m = int(t%60)+1
else :
    m = int(t%60)
if m == 0 or m == 60 :
	set_min = 00
else :
	set_min = str(60-m)
if h > 8 :
	set_hour = 8-h+24-1
	print('%d:%s'%(set_hour,set_min))

else :
	set_hour = 8-h-1
	print('0%d:%s'%(set_hour,set_min))