#include<fstream.h>
ifstream fin("flip.in");
ofstream fout("flip.out");
int a[257],s,sq,sqq,sqqq,sqqqq;
unsigned m,n,i,j;
int main(){
	fin>>n>>m; sq=0; sqq=0; sqqq=0; sqqqq=0;
	for(i=1;i<=n;i++){
		s=0;
		for(j=1;j<=m;j++){
			fin>>a[(i-1)*m+j];
			s=s+a[(i-1)*m+j];
		}
		if(s<0){
			s=0;
			for(j=1;j<=m;j++){
				a[(i-1)*m+j]=a[(i-1)*m+j]*(-1);
				s=s+a[(i-1)*m+j];
			}
		}
		sq=sq+s;
	}
	for(i=1;i<=m;i++){
		s=0;
		for(j=1;j<=n;j++)
			s=s+a[i+(j-1)*m];
		if(s<0){
			s=0;
			for(j=1;j<=n;j++){
				a[i+(j-1)*m]=a[i+(j-1)*m]*(-1);
				s=s+a[i+(j-1)*m];
			}
		}
		sqq=sqq+s;
	}
	for(i=1;i<=n;i++){
		s=0;
		for(j=1;j<=m;j++)
			s=s+a[(i-1)*m+j];
		if(s<0){
			s=0;
			for(j=1;j<=m;j++){
				a[(i-1)*m+j]=a[(i-1)*m+j]*(-1);
				s=s+a[(i-1)*m+j];
			}
		}
		sqqq=sqqq+s;
	}
	for(i=1;i<=m;i++){
		s=0;
		for(j=1;j<=n;j++)
			s=s+a[i+(j-1)*m];
		if(s<0){
			s=0;
			for(j=1;j<=n;j++){
				a[i+(j-1)*m]=a[i+(j-1)*m]*(-1);
				s=s+a[i+(j-1)*m];
			}
		}
		sqqqq=sqqqq+s;
	}
	if(sqqqq>=sqqq && sqqqq>=sqq && sqqqq>=sq) fout<<sqqqq;
	else if(sqqq>=sqqqq && sqqq>=sqq && sqqq>=sq) fout<<sqqq;
	else if(sqq>=sqqqq && sqq>=sqqq && sqq>=sq) fout<<sqq;
	else fout<<sq;
	fin.close();
	fout.close();
	return 0;
}