let A = "ACGT" and B = "AGCT" in let rec LCS [] B = 0 || LCS A [] = 0 || LCS (A.As) (B.Bs)&(A=B) = 1 + LCS As Bs || LCS A B = max (LCS A (tl B)) (LCS (tl A) B) in LCS A B --\fB Slow Longest Common Subsequence Algorithm. \fP