#include<stdio.h>
#include<string.h>
FILE*f=fopen("flip.in","r");
FILE*g=fopen("flip.out","w");
int j,k,n,m,i,s,S,max;
int a[17][17],b[17][17],v[21];
int main () {
	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;
			k--;
		}
		v[k]=1;
		memcpy(b,a,sizeof(a));
		for(i=1;i<=m;i++){
			if(v[i]==1)
				for(j=1;j<=n;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)
				S+=-s;
			else
				S=S+s;
		}

		if(S>max)
			max=S;
		S=0;
	}

	fprintf(g,"%d",max);
	fclose(f);
	fclose(g);
	return 0;
}