#include<stdio.h>  
int i,j,n,m,a[16][16],st[16],smax;  
void back(int k)  {   
	int i,j,s,x;  
	if (k==m){  
		s=0;  
		for (i=0;i<n;i++){  
			x=0;             
			for (j=0;j<m;j++)                 
				if (st[j])                
					x+=-a[i][j];                 
				else                 
					x+=a[i][j];                 
				if(x>-x)  
					s+=x;  
				else  
					s+=-x;                
		}                 
		if (smax<s)  
			smax=s;                 
		return;                 
	}  
	st[k]=0;                 
	back(k+1);                 
	st[k]=1;                 
	back(k+1);                
}  
int main(){  
	freopen("flip.in","r",stdin);  
	freopen("flip.out","w",stdout);  
	scanf("%d%d",&n,&m);  
	for(i=0;i<n;i++)  
		for(j=0;j<m;j++)  
			scanf("%d",&a[i][j]);  
	back(0);  
	printf("%d\n",smax);  
	return 0;  
}