Transform the string in the input field to the a camel case, i.e., the first letter of the words should be capitalized, except the first letter in the entire string.
hello_world
`helloWorld`
Complete the following task based on the instruction and optional input provided.### Instruction:
Transform the string in the input field to the a camel case, i.e., the first letter of the words should be capitalized, except the first letter in the entire string.

### Input:
hello_world

### Output:
`helloWorld`