感觉没毛病，为啥50分喃？？？？？以下是我的代码

import math
def is_prime(n):
    # 2 3 5 7 11 13 17 19...
    sqr = int(math.sqrt(n))
    for i in range(2,sqr+1):
        if n % i == 0:
            return "False"
    if n < 2:
        return "False"
    return "True"
s = input().strip()
dic = {}
for j in "abcdefghijklmnopqrstuvwxyz":
    dic[j] = 0
for i in s:
    dic[i] += 1
dic_values = dic.values()
count_lst = []
for i in dic_values:
    if i != 0:
        count_lst.append(i)
# print(count_lst)
# print(max(dic_values),min(dic_values)+1)
n = max(count_lst) - min(count_lst)
if is_prime(n):
    print("Lucky Word")
    print(n)
else:
    print("No Answer")
    print(0)