#include <iostream>
#include <fstream>
using namespace std;

int main()
{
	ifstream in("flip.in");
	ofstream out("flip.out");
	int a[100][100], m, n, sp = 0, sn = 0, s = 0, a1[100][100], k = 0;
	in >> n >> m;

	for (int i = 1; i <= n; i++)
		for (int j = 1; j <= m; j++)
		{
			in >> a[i][j];
			a1[i][j] = a[i][j];
		}

	for (int i = 1; i <= n; i++)
	{
		sp = 0;
		sn = 0;
		for (int j = 1; j <= m; j++)
		{
			sp += a[i][j];
		}

		for (int j = 1; j <= m; j++)
		{
			a[i][j] *= -1;
		}

		for (int j = 1; j <= m; j++)
		{
			sn += a[i][j];
		}

		if (sp > sn)
		{
			for (int j = 1; j <= m; j++)
			{
				a[i][j] *= -1;
			}
		}
	}

	for (int j = 1; j <= m; j++)
	{
		sp = 0;
		sn = 0;
		k = 0;
		for (int i = 1; i <= n; i++)
		{
			sp += a[i][j];
		}

		for (int i = 1; i <= n; i++)
		{
			a[i][j] *= -1;
		}

		for (int i = 1; i <= n; i++)
		{
			if (a[1][j] != a1[i][j]) k = 1;
			else
			{
				k = 0;
				break;
			}
		}

		if (k == 0)
			for (int i = 1; i <= n; i++)
			{
				a[i][j] *= -1;
			}

		for (int i = 1; i <= n; i++)
		{
			sn += a[i][j];
		}

		if (sp > sn)
		{
			for (int i = 1; i <= n; i++)
			{
				a[i][j] *= -1;
			}
		}
	}

	for (int i = 1; i <= n; i++)
		for (int j = 1; j <= m; j++)
			s += a[i][j];

	out << s;

	system("pause");
	return 0;
}