Given a string, find the most frequent character.
“abbcddeefffff”
In the string "abbcddeefffff", the most frequent character is 'f' which appears 6 times.
Complete the following task based on the instruction and optional input provided.### Instruction:
Given a string, find the most frequent character.

### Input:
“abbcddeefffff”

### Output:
In the string "abbcddeefffff", the most frequent character is 'f' which appears 6 times.