#include<stdio.h> 
int i,j,k,m,n,max,s,s1,a[18][18],b[18][18],v[18]; 
int main (){ 
FILE *f=fopen("flip.in","r"); 
FILE *g=fopen("flip.out","w"); 
 
 
fscanf(f,"%d %d",&n,&m); 
 
for(i=1;i<=n;i++) 
	for(j=1;j<=m;j++) 
		fscanf(f,"%d",&a[i][j]); 

 while (v[0]!=1){
	k=m;
	while(v[k]==1){
		v[k--]=0;
	}
	v[k]=1;
	 
	for(i=1;i<=n;i++) 
		for(j=1;j<=m;j++) 
			b[i][j] = a[i][j]; 
    
	for (i=1;i<=m;i++) {
		if(v[i]==1)
			for (j=1;j<=n;j++) 
				b[j][i]=-a[j][i];
	}
	s1=0;
	for(i=1;i<=n;i++){
		s=0;
		for(j=1;j<=m;j++)
			s+=b[i][j];
		if(s>0)
			s1+=s;
		else
			s1+=-s;
	}	
	
	if(s1>max)
		max=s1;
}
fprintf(g,"%d",max);
fclose(f);
fclose(g);
return 0;
}