program main
  implicit none
  character*5::time
  integer::h,m,carry
  read *,time
  read(time(1:2),'(i2)'),h
  read(time(4:5),'(i2)'),m

  if(m.ge.55) then
     carry = 1
  end if
  m = MOD(m+5,60)
  h = MOD(h+carry,24)
  print '(i2.2,":",i2.2)',h,m
end program main