`Easy`	`Codewriting` 	`300`

Find the leftmost digit that occurs in a given string.

## Example

- For `inputString = "var_1__Int"`, the output should be
`firstDigit(inputString) = '1'`;

- For `inputString = "q2q-q"`, the output should be
`firstDigit(inputString) = '2'`;

- For `inputString = "0ss"`, the output should be
`firstDigit(inputString) = '0'`.

## Input/Output

- [execution time limit] 4 seconds (go)

- [input] string inputString

    A string containing at least one digit.

    Guaranteed constraints: \
    `3 ≤ inputString.length ≤ 10`.

- [output] char

## [Go] Syntax Tips

``` go
// Prints help message to the console
// Returns a string
func helloWorld(name string) string {
    fmt.Printf("This prints to the console when you Run Tests");
    return "Hello, " + name;
}
```
