package main

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

/*
 * Complete the 'noPrefix' function below.
 *
 * The function accepts STRING_ARRAY words as parameter.
 */

type trie struct {
	wordEnd bool
	child   [10]*trie
}

func (m *trie) add(word string) {
	curr := m
	for _, r := range word {
		index := r - 'a'
		if curr.child[index] == nil {
			curr.child[index] = &trie{}
		}
		curr = curr.child[index]
	}
	curr.wordEnd = true
}

func (m *trie) find(word string) bool {
	curr := m
	for _, r := range word {
		index := r - 'a'
		if curr.child[index] != nil {
			curr = curr.child[index]

			if curr.wordEnd {
				return true
			}
		} else {
			return false
		}
	}
	return true
}

func noPrefix(words []string) {
	tree := &trie{}

	for _, word := range words {
		if tree.find(word) {
			fmt.Print("BAD SET\n", word)
			return
		}
		tree.add(word)
	}
	fmt.Println("GOOD SET")
}
func main() {
	reader := bufio.NewReaderSize(os.Stdin, 16*1024*1024)

	nTemp, err := strconv.ParseInt(strings.TrimSpace(readLine(reader)), 10, 64)
	checkError(err)
	n := int32(nTemp)

	var words []string

	for i := 0; i < int(n); i++ {
		wordsItem := readLine(reader)
		words = append(words, wordsItem)
	}

	noPrefix(words)
}

func readLine(reader *bufio.Reader) string {
	str, _, err := reader.ReadLine()
	if err == io.EOF {
		return ""
	}

	return strings.TrimRight(string(str), "\r\n")
}

func checkError(err error) {
	if err != nil {
		panic(err)
	}
}