def lcs(s1, s2, i, j):
if i == <NUM_LIT:0> or j == <NUM_LIT:0>:<EOL><INDENT>return <NUM_LIT:0><EOL><DEDENT>elif s1[i - <NUM_LIT:1>] == s2[j - <NUM_LIT:1>]:<EOL><INDENT>return <NUM_LIT:1> + lcs(s1, s2, i - <NUM_LIT:1>, j - <NUM_LIT:1>)<EOL><DEDENT>else:<EOL><INDENT>return max(lcs(s1, s2, i - <NUM_LIT:1>, j), lcs(s1, s2, i, j - <NUM_LIT:1>))<EOL><DEDENT>
The length of longest common subsequence among the two given strings s1 and s2