import java.util.*
const val L = 3

fun main(args: Array<String>) {
	val cin = Scanner(System.`in`)
	val N = cin.nextInt()
	val M = cin.nextInt()

	val cups = MutableList(L + 1) { 0 }
	cups[N] = 1

	for (i in 0 until M) {
		val P = cin.nextInt()
		val Q = cin.nextInt()

		cups[P] = cups[Q].also {
			cups[Q] = cups[P]
		}
	}
	println(cups.indexOf(cups.max()))
}