#include <cstdio>

int main()
{
	FILE *f = fopen("flip.in", "r");
	FILE *g = fopen("flip.out", "w");
	
	int mat[17][17], m,n, max = -999999999;
	char stiva[17], level = 1;
	
	fscanf(f, "%d %d", &n, &m);
	
	for (int i = 1 ; i <= n ; ++i)
		for (int j = 1; j <= m ; ++j)
			fscanf(f, "%d", &mat[i][j]);
	
	stiva[1] = -1;
	do 
	{
		bool as = false;
		if (stiva[level] < 1)
		{
			as = true;
			stiva[level]++;
		}
		
		if (level == m && as)
		{
		
			int sum = 0;
			for (int i = 1 ; i <= n ; ++i)
			{
				int lineSum = 0;
				for (int j = 1 ; j <= m ; ++j)
				{
					if (stiva[j])
						lineSum += -mat[i][j];
					else
						lineSum += mat[i][j];
				}
				if (lineSum < 0)
					sum += -lineSum;
				else
					sum += lineSum;
			}
			if (sum > max)
				max = sum;
		
		}
		else if (as == false)
		{
			stiva[level] = -1;
			level--;
		}
		else
		{
			level++;
			stiva[level] = -1;
		}
		
	} while (level > 0);	
		
	fprintf(g, "%d\n", max);
		
	return 0;
}