Given two strings word1 and word2, return the minimum number of operations required to convert word1 to word2.

You have the following three operations permitted on a word:

• Insert a character
• Delete a character
• Replace a character

Example 1:

Input:
horse
ros
Output: 3

(horse → rorse → rose → ros)

Example 2:

Input:
intention
execution
Output: 5

Constraints:

• 0 ≤ word1.length, word2.length ≤ 500
• word1 and word2 consist of lowercase English letters

Input format: Two lines, each containing a string.

Output format: Minimum edit distance.