#include <iostream>
#include <cmath>
using namespace std;
 
int a[105][105];
int main() 
{
	int n;
	cin>>n;
	for(int i = 0; i < n; ++i){
		for(int j = 0; j < n; ++j){
			cin>>a[i][j];
		}
	}
	int sum1 = 0, sum2 = 0;
	for(int i=0; i < n; ++i){
		sum1 += a[i][i];
		sum2 += a[i][n-i-1];
	}
	cout<< abs(sum1-sum2);
	// your code goes here
	return 0;
}