#include<fstream.h>
int n,m,i,j,sum,s1,s2,max,a[20][20],b[50];
ifstream f("flip.in");
ofstream g("flip.out");
int main(){
f>>n>>m;
for(i=1;i<=n;i++)
for(j=1;j<=m;j++)
	{f>>a[i][j];
	max+=a[i][j];
	}
b[1]=1;
for(;b[n]==0;b[1]++)
{for(j=1;j<=n;j++)
	if(b[j]==2)
		{b[j+1]++;
		b[j]=0;}
sum=0;
for(i=1;i<=n;i++){s1=0;s2=0;
for(j=1;j<=m;j++)
	{if(b[j])
		{s1-=a[i][j];s2+=a[i][j];}
	else
		{s1+=a[i][j];s2-=a[i][j];}
	}
if(s1>s2)
	sum+=s1;
else
	sum+=s2;}

if(sum>max)
	max=sum;
}
g<<max;
f.close();
g.close();
return 0;}