n = int(input())
kaisuu = int(input())
i = 0
basho = [0, 0, 0]
n -= 1
copy = 0
basho[n] = 1
while i < kaisuu:
    a, b = input().split()
    a = int(a)
    a -= 1
    b = int(b)
    b -= 1
    copy = basho[a]
    basho[a] = basho[b]
    basho[b] = copy
    i += 1
check = 0
i = 0
while check == 0:
    if basho[i] == 1:
        break
    i += 1
i += 1
print(i)