PROGRAMMING:Copy of two strings
Copy string a to string B, and then output string B (the length of a, B character array is less than 20)（ You must use the gets function to enter a string)
###Input format:
Enter any string a, less than 20 in length.
###Output format:
String B is: String B.
###Input example:
Here is a set of inputs. For example:
```in
I am a student.
```
###Output example:
The corresponding output is given here. For example:
```out
string a is:I am a student.
string b is:I am a student.
```
answer：If there is no answer, please comment
###Input format:
Enter any string a, less than 20 in length.
###Output format:
String B is: String B.
###Input example:
Here is a set of inputs. For example:
```in
I am a student.
```
###Output example:
The corresponding output is given here. For example:
```out
string a is:I am a student.
string b is:I am a student.
```
answer：If there is no answer, please comment