package main

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

func main()  {
	sc := bufio.NewScanner(os.Stdin)
	var s string
	if sc.Scan() {
		s = sc.Text()
	}
	slice := strings.Split(s, " ")
	sum := 0
	for i := 0; i < len(slice); i += 2 {
		a, _ := strconv.Atoi(slice[i])
		sum += a
	}
	t := sum % 2
	if t != 0 {
		fmt.Print(":-(")
	} else {
		fmt.Print(":-)")
	}
}