#include<stdio.h>
using namespace std;
#define dim 17
long i,n,m,j,s,mat[dim][dim];
int main()
{
FILE *f=fopen("flip.in","r"), *g=fopen("flip.out","w");

fscanf(f,"%ld %ld",&n,&m);

for(i=1;i<=n;i++)
{s=0;
	for(j=1;j<=m;j++)
	{
		fscanf(f,"%ld",&mat[i][j]);
		s+=mat[i][j];
	}
mat[i][0]=s;
}

for(i=1;i<=n;i++)
	if(mat[i][0]<0)
		for(j=1;j<=m;j++)
			mat[i][j]=-mat[i][j];

for(i=1;i<=m;i++)
{s=0;
	for(j=1;j<=n;j++)
		s+=mat[j][i];
mat[0][i]=s;
}			

for(i=1;i<=m;i++)
	if(mat[0][i]<0)
		for(j=1;j<=n;j++)
			mat[j][i]=-mat[j][i];
	s=0;
for(i=1;i<=n;i++)
	for(j=1;j<=m;j++)
		s+=mat[i][j];
	
fprintf(g,"%ld\n",s);

return 0;}