def skjkasdkd(lst):
    def isPrime(n):
        for i in range(2,int(n**0.5)+1):
            if n%i==0:
                return False
        return True
    maxx = 0
    i = 0
    while i < len(lst):
        if(lst[i] > maxx and isPrime(lst[i])):
            maxx = lst[i]
        i+=1
    result = sum(int(digit) for digit in str(maxx))
    return result
from typing import List
def mean_absolute_deviation(numbers: List[float]) -> float:
    mean = sum(numbers) / len(numbers)
    return sum(abs(x - mean) for x in numbers) / len(numbers)