#include <fstream>
using namespace std;
ifstream f("flip.in");
ofstream g("flip.out");
int n,m,sc,sl,a[17][17],i,Sum,S,s,j,c,l;
int main()
{   f>>n>>m;
    for(i=1;i<=n;++i)
        for(j=1;j<=m;++j)
            f>>a[i][j];
    int nr=100;
     for(i=1;i<=n;++i)
        for(j=1;j<=m;++j)
            Sum+=a[i][j];
    sc=sl=999999999;
    while(nr--)
    {for(i=1;i<=m;++i)
        {for(j=1;j<=n;++j)
            s+=a[j][i];
    if(s<sc){sc=s;c=i;s=0;}
        else s=0;}
    s=0;
   for(i=1;i<=n;++i)
        {for(j=1;j<=m;++j)
            s+=a[i][j];
        if(s<sl){sl=s;l=i;s=0;}
            else s=0;}
    s=0;
    if(sc<sl)for(i=1;i<=n;++i)a[i][c]=a[i][c]*(-1);
        else for(i=1;i<=m;++i)a[l][i]=a[l][i]*(-1);
    for(i=1;i<=n;++i)
        for(j=1;j<=m;++j)
           S+=a[i][j];
    if(S>Sum)Sum=S;S=0;
    nr--;
    sl=sc=999999999;
    }
    g<<Sum;
    return 0;
}