#coding: UTF-8

import sys
from math import pi
from collections import deque
from functools import reduce

### defs ###

### main ###
N = int(sys.stdin.readline())
M = int(sys.stdin.readline())
PQ = map(lambda s:s.split(), sys.stdin.readlines())
PQ = map(lambda lst: list(map(int,lst)), PQ)
maru=[0,0,0]
maru[N-1]=1
for pq in PQ:
	p = pq[0]-1
	q = pq[1]-1
	maru[p],maru[q] = maru[q],maru[p]
print(maru.index(1)+1)