T=input()
# T='23:59'
hour=int(T[:2])
minute=int(T[3:])
if minute+5>=60:
	sabun=minute+5-60
	minute=sabun
	if hour==23:
		hour=0
	else:
		hour+=1
else:
	minute+=5
out=str(hour) if hour>=10 else '0'+str(hour)
out+=':'
out+=str(minute) if minute>=10 else '0'+str(minute)
print(out)