Format the following string according to the given rules.
Input: This is A StrinG
Rules: Start with uppercase letter; No capitalized letters elsewhere
This is a string.
Complete the following task based on the instruction and optional input provided.### Instruction:
Format the following string according to the given rules.

### Input:
Input: This is A StrinG
Rules: Start with uppercase letter; No capitalized letters elsewhere

### Output:
This is a string.