#include <stdio.h>
#include <malloc.h>
//check the data types such as ‘long int **’ but argument is of type ‘long int (*)[16]’
#define MAX_SIZE 16


struct matrix {
	long int mat[16][16];
	int n,m;
};

char check_positive_row(struct matrix *mat, int row);
void flip_row(struct matrix *mat, int row);

char check_positive_col(struct matrix *mat,  int col);
void flip_col(struct matrix *mat,  int col);

struct matrix compute_row(struct matrix *mat);
struct matrix compute_col(struct matrix *mat);

long int sum(struct matrix *mat);

int main ()
{
FILE *in = NULL, *out = NULL;
int n,m,i,j;
long int **mat = NULL;
char changed = 1;
long int sum2 = 0, sum1=0;
long int prevsum = 0;
struct matrix inputMat, rowmat, colmat;

if ((in = fopen ("flip.in", "r")) == NULL)
	{printf ("Input could not be opened\n"); return -1; }
if ((out = fopen ("flip.out","w")) == NULL)
	{printf ("Output could not be opened \n"); return -1;}

fscanf(in, "%d %d\n",&inputMat.n, &inputMat.m);


for (i = 0 ; i < inputMat.n ; ++i)
   for (j = 0 ; j < inputMat.m ; ++j){
	fscanf (in , "%ld", &inputMat.mat[i][j]);
}
prevsum = sum (&inputMat);

while (changed){
	changed = 0;
 	
	colmat = compute_col(&inputMat);	
	rowmat = compute_row(&inputMat);

	sum1 = sum(&colmat);	
	sum2 = sum(&rowmat);
 	if (sum1 > sum2){
		if (sum1 > prevsum ){
			changed = 1;
			inputMat = colmat;
		}
	}
	else
	{
		if (sum2 > prevsum ){
			changed = 1;
			inputMat = rowmat;
		}
	}
		
	prevsum = sum(&inputMat);
}

// calculate line and column
//check which has a greater sum
// check whether the greater sum is the same as the previous step, if it is then we have finished

fprintf(out , "%ld\n",prevsum );

fclose(in);
fclose(out); 
return 0;
}

long int sum (struct matrix *mat){
int i,j;
long int result=0;

for (i = 0; i < mat->n; i++ )
for (j =0 ; j < mat->m ; ++j){
	result += mat->mat[i][j]; 
}
return result;	
}

struct matrix compute_col(struct matrix *mat){
int i ;
struct matrix result = *mat;

	for (i = 0 ; i < result.m; i++){
		if (!check_positive_col(&result, i))
			flip_col(&result, i);
	}

return result;		
}

struct matrix compute_row(struct matrix *mat){
int i ;
struct matrix result = *mat;

	for (i = 0 ; i < result.n; i++){
		if (!check_positive_row(&result, i))
			flip_row(&result, i);
	}
return result;
}

char check_positive_col(struct matrix *s_mat,  int col){
long int sum = 0, i= 0;

for (i =0 ; i < s_mat->n ; ++i){
	sum += s_mat->mat[i][col];
}

if (sum < 0) return 0;
return 1;
}


void flip_col(struct matrix *s_mat, int col){
long int i = 0 ;
//init result

for (i =0 ; i < s_mat->n ; ++i){
	  s_mat->mat[i][col] *= (-1);
}
}

char check_positive_row(struct matrix *s_mat , int row){
long int sum = 0;
int i=0;
for (i = 0; i < s_mat->m ; i++){
	sum += (*s_mat).mat[row][i];
}

if (sum < 0 ) return 0;
return 1;
}

void flip_row(struct matrix *s_mat, int row){
	int i = 0;
	for (i = 0 ; i < s_mat->m ; ++i  )
		 s_mat->mat[row][i] *= (-1);
}