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#!/usr/bin/python

from sys import argv

mem = [{}, {}]

def flip(x, y):
    if y not in mem[x]:
        mem[x][y] = 1
    else:
        mem[x][y] = 1 - mem[x][y]
    return mem[x][y]

with open(argv[1]) as f:
    lines = f.readlines()

while True:
    for line in lines:
        l = list(map(int, line.split()))
        x = l[0]
        for i in range(1, len(l)):
            x = flip(x, l[i])
        print(x)
    if 0 not in mem[0] or mem[0][0] == 0:
        exit()