# -*- coding: utf-8 -*-

T = input()

hh, mm = map(int, T.split(':'))

if mm + 5 > 59:
    mm -= 55
    if hh + 1 > 23:
        hh = 0
    else:
        hh += 1
else:
    mm += 5

hh = '0' + str(hh) if hh < 10 else str(hh)
mm = '0' + str(mm) if mm < 10 else str(mm)

print(hh + ':' + mm)