Given a square matrix of size N×N, calculate the absolute difference between the sums of its diagonals. 
-----Input-----
The first line contains a single integer N. The next N lines denote the matrix's rows, with each line containing N space-separated integers describing the columns.
-----Output-----
Print the absolute difference between the two sums of the matrix's diagonals as a single integer.
-----Constraints-----
1<=N<=10
-----Example-----
Input:
3
11 2 4
4 5 6
10 8 -12
Output:
15
-----Explanation-----
The primary diagonal is: 
11
5
-12
Sum across the primary diagonal: 11 + 5 - 12 = 4
The secondary diagonal is:
4
5
10
Sum across the secondary diagonal: 4 + 5 + 10 = 19 
Difference: |4 - 19| = 15
def diagonal_difference(matrix):
 l = sum(matrix[i][i] for i in range(N))
 r = sum(matrix[i][N-i-1] for i in range(N))
 return abs(l - r)

matrix = []
N = eval(input())
for _ in range(N):
 matrix.append(list(map(int, input().split())))

print(diagonal_difference(matrix))
def diagonal_difference(matrix):
 l = sum(matrix[i][i] for i in range(N))
 r = sum(matrix[i][N-i-1] for i in range(N))
 return abs(l - r)

matrix = []
N = eval(input())
for _ in range(N):
 matrix.append(list(map(int, input().split())))

print(diagonal_difference(matrix))