import math def is_perfect_square(num): root = int(math.sqrt(num)) return root * root == num def find_max_non_square(numbers): max_non_square = float('-inf') for num in numbers: if not is_perfect_square(num): max_non_square = max(max_non_square, num) return max_non_square def main(): n = int(input().strip()) numbers = list(map(int, input().strip().split())) result = find_max_non_square(numbers) print(result) if __name__ == "__main__": main()