"""
Given an array of integers arr, a lucky integer is an integer which has a frequency in the array equal to its value.

Return a lucky integer in the array. If there are multiple lucky integers return the largest of them. If there is no lucky integer return -1.

Example 1:
Input: arr = [2,2,3,4]
Output: 2
Explanation: The only lucky number in the array is 2 because frequency[2] == 2.

Example 2:
Input: arr = [1,2,2,3,3,3]
Output: 3
Explanation: 1, 2 and 3 are all lucky numbers, return the largest of them.

Example 3:
Input: arr = [2,2,2,3,3]
Output: -1
Explanation: There are no lucky numbers in the array.

Example 4:
Input: arr = [5]
Output: -1

Example 5:
Input: arr = [7,7,7,7,7,7,7]
Output: 7

"""


class Solution:
    def findLucky(self, arr):
        res = [arr.count(i) for i in arr if i == arr.count(i)]
        return max(res) if res else -1


if __name__ == "__main__":
    s = Solution()
    print(s.findLucky([2, 2, 3, 4]))
