import sys
import web3

f = open(sys.argv[1], 'r')
z = b''
for i in range(32):
    z += b'\x00'
while True:
    l = f.readline()
    if l == '':
        break
    #print('line {}'.format(l))
    h = web3.Web3.keccak(text=l)
    z = bytes([a ^ b for a, b in zip(h, z)])
    #print(h.hex(), z.hex())
f.close()
print(h[:4].hex())