h ,m = gets.split(":").map(&:to_i)
def digitize(num)
    if 0 <= num && num <= 9 
        return "0" + num.to_s
    else
        return num.to_s
    end
end

if (m+5 >= 60) && (h+1 >= 24)
    puts digitize(0) + ":" + digitize(m + 5 - 60)
elsif (m+5 >= 60)
    puts digitize(h+1)+":"+ digitize(m + 5)
else 
    puts digitize(h)+":"+ digitize(m + 5)
end