how to find max occurrence of a letter in a string

how can I do something like this?

string = "ABFFFBFFFFFBF"
letter = "F"

maximum occurrence of F is FFFFF so output is: 5
anyone help?

>Solution :

There is probably a more Pythonic way to do this, but this function will do the job:

def maxConsecutiveOccurrences(letter, string):
    count = 0
    maxCount = 0
    for ch in string:
        if ch == letter:
            count += 1
        else:
            count = 0
        if count > maxCount:
            maxCount = count
    return maxCount

maxConsecutiveOccurrences("F", "ABFFFBFFFFFBF") returns 5