# Problem Link : https://leetcode.com/problems/matrix-diagonal-sum/

class Solution(object):
    def diagonalSum(self, array):
        """
        :type array: List[List[int]]
        :rtype: int
        """
        n = len(array)
        primary = 0
        secondary = 0;
        for i in range(0, n):
            primary += array[i][i]
            secondary += array[i][n-i-1]
        if (n % 2 == 0): return primary + secondary
        else: return primary + secondary - array[n//2][n//2]