#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;
}