#include<stdio.h> 
int i,j,k,m,n,max,s,s1,a[10000][10000],b[10000][10000],v[10000]; 
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=n;
	while(v[k]==1)
		v[k--]=0;
	v[k]=1;
	    
    
	
	
	
  
for (i=1;i<=m;i++) 
	if(v[i]==1)
		for (j=1;j<=m;j++) 
		b[j][i]=-b[j][i];

    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;


fclose(f); 
fclose(g); 
return 0;
 }