PROGRAMMING:Editing distance problem

Let a and B be two strings. Convert string a to string B with minimal character manipulation. The character operation includes (1) deleting a character（ 2) Insert a character（ 3) Change one character to another. The minimum number of character operands used to transform string a into string B is called the edit distance from string a to string B, which is denoted as D (a, b). For the given string a and string B, the edit distance D (a, b) is calculated.
###Input format:
The first line is string a, and the second line of the file is string B.
Tip: the length of the string does not exceed 2000 characters.
###Output format:
Output edit distance D (a, b)
###Input example:
Here is a set of inputs. For example:
```in
fxpimu
xwrs
```
###Output example:
The corresponding output is given here. For example:
```out
five
```







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