#include <stdio.h>
int a[32][32], sol = 0;

int main()
{
	int i, j, k, l, now, n, m;
	freopen("flip.in", "r", stdin);
	freopen("flip.out", "w", stdout);
	scanf("%d %d", &n, &m);
	for (i = 0; i < n; ++i)
		for (j = 0; j < m; ++j)
			scanf("%d", &a[i][j]);
	for (i = 0; i < (1 << n); ++i)
	{
		for (j = now = 0; j < m; ++j)
		{
			for (k = l = 0; k < n; ++k)
				if ((1 << k) & i)
					l -= a[k][j];
				else
					l += a[k][j];
			if (l < 0)
				now -= l;
			else
				now += l;
		}
		if (now > sol)
			sol = now;
	}
	printf("%d\n", sol);
	return 0;
}