In this task, you are given a string with duplicate characters ocurring in the string. You need to return the character which is ocurring with the maximum frequency. In case of a tie, return the character with the least ascii value.

[EX Q]: roamljlzjxnpsjvahmyeyhzgoekwxsojqlupwuoyop
[EX A]: o

[EX Q]: yypvxistmjzuqxcnzvegzwjymdiuwxkodzorjcsb
[EX A]: z

[EX Q]: aidsqyawuvenjzkansacvfqentxwgxbfkssnjmwsxzg
[EX A]:
s