#include<stdio.h> 
int n,i,j,k,v[20*20],a[20][20],b[20][20],x,z,suma,max,m,y; 
int main() { 
    
	FILE*f=fopen("flip.in","r"); 
	FILE*g=fopen("flip.out","w"); 
	max=-4000; 
    
	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]; 
                 
	suma=0; 

	for(i=1;i<=n;i++){ 
		x=0; 
		for(j=1;j<=m;j++) 
			x+=b[i][j]; 
		if(x>0) 
			suma+=x; 
		else
			suma+=-x; 
		} 
		if(suma>max) 
		max=suma;
	} 
   
	fprintf(g,"%d",max);
	
	fclose(f); 
	fclose(g); 
   
	return 0; 
}