Merge the two sentences given such that the resultant sentence is grammatically correct.
She is sitting. She is reading a book.
She is sitting and reading a book.
Complete the following task based on the instruction and optional input provided.### Instruction:
Merge the two sentences given such that the resultant sentence is grammatically correct.

### Input:
She is sitting. She is reading a book.

### Output:
She is sitting and reading a book.