#include<stdio.h>
#include<string.h>
#define dim 17
using namespace  std;

int A[dim][dim], B[dim][dim];

int main()
{ int i, j, N, M, k, S, sum, max = 0;

	freopen("flip.in","r", stdin);
	freopen("flip.out", "w", stdout);
	
	scanf("%d%d", &N,&M);
	for(i = 1; i <= N; i++)
		for(j = 1; j <= M; j++)
			scanf("%d", &A[i][j]);
	
	for(i = 0; i <= (1<<N)-1; i++)
	{
		memcpy(B, A, sizeof(B));
		
		for(j = 0; j <= N-1; j++)
			if(i & (1<<j))
				for(k = 1; k <= M; k++)
					B[j+1][k] *=-1;
	
		sum = 0;
		for(j = 1; j <= M; j++)
		{
			S = 0;
			for(k = 1; k <= N; k++)
				S += B[k][j];
		
			if(S < 0)
				sum += S*-1;
			else sum += S;
		}
		
		if(sum > max) max = sum;
	}
	
	printf("%d\n", max);
	return 0;
	
}