input: Write a python function to concatenate two binary strings such that each bit in the resultant string is '1' if at least one of the corresponding bits in the input strings is '1', otherwise '0'.
  assert concatTwoBinStrings("10101", "101")=="111111"
  assert concatTwoBinStrings("1100", "0011")=="1111"
  assert concatTwoBinStrings("0000", "0000")=="00000000"
output: def concatTwoBinStrings(bin1, bin2):
      max_len = max(len(bin1), len(bin2))
      bin1 = bin1.zfill(max_len)
      bin2 = bin2.zfill(max_len)
      result = ''
      for b1, b2 in zip(bin1, bin2):
          result += '1' if b1 == '1' or b2 == '1' else '0'
      return result