import bisect
import copy
import decimal
import fractions
import heapq
import itertools
import math
import random
import sys
from collections import Counter, deque,defaultdict
from functools import lru_cache,reduce
from heapq import heappush,heappop,heapify,heappushpop,_heappop_max,_heapify_max
def _heappush_max(heap,item):
    heap.append(item)
    heapq._siftdown_max(heap, 0, len(heap)-1)
def _heappushpop_max(heap, item):
    if heap and item < heap[0]:
        item, heap[0] = heap[0], item
        heapq._siftup_max(heap, 0)
    return item
from math import gcd as GCD
read=sys.stdin.read
readline=sys.stdin.readline
readlines=sys.stdin.readlines

N=int(readline())
M=int(readline())
ans_lst=[False]*3
ans_lst[N-1]=True
for _ in range(M):
    P,Q=map(int,readline().split())
    P-=1;Q-=1
    ans_lst[P],ans_lst[Q]=ans_lst[Q],ans_lst[P]
for ans in range(3):
    if ans_lst[ans]:
        ans+=1
        break
print(ans)