#include <iostream>
#include <fstream>
using namespace std;
int v[17][17],n,m,i,j,s,s1;
int main ()
{
    ifstream ci ("flip.in");
    ofstream co ("flip.out");
    ci>>n>>m;
    for (int i=1;i<=n;++i)
    {
        for (int j=1;j<=m;++j)
        {
            ci>>v[i][j];
        }
    }
    for (int i=1;i<=n;++i)
    {
         for (int j=1;j<=m;++j)
         {
             s=s+v[i][j];
         }
         for (int j=1;j<=m;++j)
         {
             s1=s1+(v[i][j]*-1);
         }
         if (s1>s)
         {
             for (int j=1;j<=m;++j)
             {
                 v[i][j]=v[i][j]*-1;
             }
         }
        s=0;
        s1=s;
    }
    s=0;
    s1=0;
    for (int i=1;i<=m;++i)
    {
         for (int j=1;j<=n;++j)
         {
             s=s+v[j][i];
         }
         for (int j=1;j<=n;++j)
         {
             s1=s1+(v[j][i]*-1);
         }
         if (s1>s)
         {
             for (int j=1;j<=n;++j)
             {
                 v[j][i]=v[j][i]*-1;
             }
         }
        s=0;
        s1=s;
    }
    s=0;
    for (int i=1;i<=n;++i)
    {
         for (int j=1;j<=m;++j)
         {
             s=s+v[i][j];
         }
    }
    co<<s;
    return 0;
}