text: class Solution:
      def numSpecial(self, mat: List[List[int]]) -> int:
          specials = 0
          for i in range(len(mat)):
              for j in range(len(mat[0])):
                  if mat[i][j] == 1 and sum(mat[i]) == 1 and sum(row[j] for row in mat) == 1:
                      specials += 1
          return specials