#include <stdio.h>
FILE *f;
int m,n;
int main(void){
	int i,j;
	f=fopen("flip.in","r");
	fscanf(f,"%d %d",&m,&n);
    int a[m][n];
 	for (i=1;i<=m;i++){
		for (j=1;j<=n;j++){
			fscanf(f,"%d",&a[i][j]);
		}
	}
	fclose(f);
	int s1=0,s2=0;
	for (j=1;j<=n;j++){
		for (i=1;i<=m;i++){
			s1+=a[i][j];
			
		   	s2+=a[i][j]*(-1); // Atentie//
		   	
		}
		
		if (s1<s2){
			for (i=1;i<=m;i++){
				a[i][j]=a[i][j]*(-1);
				
				
			}
		}
		else{}
		
		s1=0;
		s2=0;
	}
	for (i=1;i<=m;i++){
		for (j=1;j<=n;j++){
			s1+=a[i][j];
			s2+=a[i][j]*(-1); // Atentie//
		}
		if (s1<s2){
			for (j=1;j<=n;j++){
				a[i][j]=a[i][j]*(-1);
			}
		}
		else{
			
		}
		s1=0;
		s2=0;
	}
	
	int s=0;
	for (i=1;i<=m;i++){
		for (j=1;j<=n;j++){
			s+=a[i][j];
			
		}
		
	}
	f=fopen("flip.out","w");
	fprintf(f,"%d",s);
	
	fclose(f);	
}