Nonrepeating Character

Have the function NonrepeatingCharacter(str) take the str parameter being passed, which will contain only alphabetic characters and spaces, and return the first non-repeating character. For example: if str is "agettkgaeee" then your program should return k. The string will always contain at least one character and there will always be at least one non-repeating character.

Examples

Input: "abcdef"
Output: a

Input: "hello world hi hey"
Output: w