<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _len_lcs(x, y):
 """Returns the length of the Longest Common Subsequence between two seqs. Source: http://www.algorithmist.com/index.php/Longest_Common_Subsequence Args: x: sequence of words y: sequence of words Returns integer: Length of LCS between x and y """

  table = _lcs(x, y)
  n, m = len(x), len(y)
  return table[n, m]