백준 1547 파이썬

location=[0,1,0,0]

num = int(input())

for i in range(num):

    a,b = map(int, input().split(" "))

    if location[a] == 1 or location[b] == 1:

        temp = location[a]

        location[a] = location[b]

        location[b] = temp

print(location.index(1))