package main

import (
	"fmt"
	"os"
	"strconv"
	"strings"
	"time"
)

func main() {
	var s string
	fmt.Scan(&s)
	h, _ := strconv.Atoi(strings.Split(s, ":")[0])
	m, _ := strconv.Atoi(strings.Split(s, ":")[1])
	t := time.Date(1, 1, 1, h, m, 0, 0, time.Local)
	fmt.Println(t.Add(5 * time.Minute).Format("15:04"))
	os.Exit(0)
}