#include<iostream>
#include<fstream>

int invarte(int n, int m, long x[17][17])
{	
	int b;
	for (int i = 1; i <= n; i++)
	{
		b = 0;
		for (int j = 1; j <= m; j++)
			b=b+x[i][j];
		x[i][0] = b;
	}
	for (int i = 1; i <= n; i++)
	{
		if(x[i][0]<0)
		for (int j = 1; j <=m; j++)
			x[i][j]= x[i][j]*(-1);
		x[i][0] = -b;
	}
	for (int j = 1; j <=m; j++)
	{
		b = 0;
		for (int i = 1; i <= n; i++)
			b = b + x[i][j];
		x[0i][j] = b;
	}
	for (int j = 1; j <= m; j++)
	{
		if (x[0][j] < 0)
			for (int i = 1; i <=n; i++)
				x[i][j] = x[i][j] * (-1);
		x[0][j] = -b;
	}
	for (int i = 1; i <= n; i++)
		for (int j = 1; j <= m; j++)
			b = b + x[i][j];
	return b;
}
using namespace std;
int main()
{
	ifstream f("flip.in");
	ofstream g("flip.out");
	int n, m;
	long x[17][17];
	f >> n >> m;
	for (int i = 1; i < n; i++)
		for (int j = 1; j < m; j++)
			f >> x[i][j];
	g << invarte( n, m, x[17][17]);
	f.close();
	g.close();
}