N = int(input())
M = int(input())
cups = [False,False,False,False]
cups[N] = True

for _ in range(M):
	P,Q = map(int,input().split())
	if cups[P]:
		cups[Q] = True
		cups[P] = False
	elif cups[Q]:
		cups[P] = True
		cups[Q] = False

for idx,item in enumerate(cups):
	if item:
		print(idx)
		break