#include <iostream>
#include <fstream>

std::ifstream f("flip.in");
std::ofstream g("flip.out");

int main()
{
	int m, n, tabla[15][15], Suma{ 0 };
	f >> n >> m;
	for (int i = 0; i <n; i++)
	{
		int SumaLinie{ 0 };
		for (int j = 0; j <m; j++)
		{
			f >> tabla[i][j];
			SumaLinie += tabla[i][j];
		}
		if (SumaLinie > 0)
			Suma += SumaLinie;
		else
			Suma -= SumaLinie; 
	}
	for (int i = 0; i <m; i++)
	{
		int SumaColoana{ 0 };
		for (int j = 0; j <n; j++)
			SumaColoana += tabla[j][i];
		if (SumaColoana < 0)
			Suma -= SumaColoana * 2;
	}
	g << Suma;

}