package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Scan()
	line := scanner.Text()
	var n, m int
	fmt.Sscanf(line, "%d %d", &n, &m)
	var times []int64
	var timeStrs []string
	daysInMonth := []int{0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
	for scanner.Scan() {
		line = scanner.Text()
		month, _ := strconv.Atoi(line[5:7])
		day, _ := strconv.Atoi(line[8:10])
		hour, _ := strconv.Atoi(line[11:13])
		minute, _ := strconv.Atoi(line[14:16])
		sec, _ := strconv.Atoi(line[17:19])
		totalDays := 0
		for mo := 1; mo < month; mo++ {
			totalDays += daysInMonth[mo]
		}
		totalDays += day - 1
		totalSec := int64(totalDays)*86400 + int64(hour)*3600 + int64(minute)*60 + int64(sec)
		times = append(times, totalSec)
		timeStrs = append(timeStrs, line[0:19])
	}
	len_ := len(times)
	left := 0
	ans := -1
	for i := 0; i < len_; i++ {
		for left <= i && times[left] < times[i]-int64(n) {
			left++
		}
		count := i - left + 1
		if count >= m {
			ans = i
			break
		}
	}
	if ans == -1 {
		fmt.Println(-1)
	} else {
		fmt.Println(timeStrs[ans])
	}
}