def diagonalDifference(arr):
    L = R = 0
    n = len(arr[0])
    for i in range(n):
        L += arr[i][i]
        R += arr[i][n-1-i ]
    return abs(L-R)
		
		or else :
		

def diagonalDifference(n,arr):
L = R = 0
for i in range(n):
L += arr[i][i]
R += arr[i][n-1-i ]
return abs(L-R)

result = diagonalDifference(n,arr)