import java.util.Scanner

var input = Scanner(System. `in`)

fun inputList(testCase: Int): MutableList<String>{
	var list: MutableList<String> = mutableListOf()
	for(i in 1..testCase) list.add(input.next())
	return list
}

fun jugdeWrong(list: MutableList<String>): String{
	var result: String = ""
	for(item: String in list){
		var str = input.next()
		if(item != str) result = "$item\n$str"
	}
	return result
}

fun main(args: Array<String>){
	var testCase: Int = input.nextInt()
	var list: MutableList<String> = inputList(testCase)
	println( jugdeWrong(list) )
}