a, b, s = gets.split
a = a.to_i
b = b.to_i
q, x = s.match(/([+-])([0-9]+\.?[0-9]*)/)[1..2]
x = x.to_f
u = a * 60 + b + (q == ?- ? -1 : 1) * x * 60 + 15 * 60
u = u.to_i
u %= 1440
u += 1440
a = u / 60 % 24
b = u % 60
puts "#{a.to_s.rjust 2, ?0}:#{b.to_s.rjust 2, ?0}"