#include<fstream.h>
int main()   
{   
ifstream f("flip.in");   
ofstream g("flip.out");   
long a[30][30],b[30][30],smax=0,scol=0,stemp=0;   
int n,m,st[20],k,j,i;   
f>>n>>m;   
for (i=1;i<=n;i++) for (j=1;j<=m;j++) {f>>a[i][j];smax+=a[i][j];}   
k=1;   
st[k]=-1;   
while (k)   
     {   
     st[k]++;   
     if (st[k]<=1) if (k==n)   
         {   
         for (i=1;i<=n;i++) for (j=1;j<=m;j++) if (st[i]) b[i][j]=-a[i][j];   
                               else b[i][j]=a[i][j];   
         stemp=0;   
         for (j=1;j<=m;j++)   
            {   
            scol=0;   
            for (i=1;i<=n;i++) scol+=b[i][j];   
            if (scol<0) stemp=stemp+(-scol);   
            else stemp=stemp+scol;   
            }   
         if (stemp>smax) smax=stemp;   
         }   
           else   
         {   
         k++;   
         st[k]=-1;   
         }   
     else k--;   
     }   
g<<smax;   
f.close();   
g.close();   
return 0;   
}