#include <iostream>
#include <fstream>
using namespace std;
ifstream f("flip.in");
ofstream g("flip.out");
int a[100][100],b[1000],c[10000],n,m,s,i,j;
int main()
{
    f>>n>>m;
    for (i=1;i<=n;i++)
     for (j=1;j<=m;j++)
     {
         f>>a[i][j];
         b[i]+=a[i][j];
         c[j]+=a[i][j];
     }
     for (i=1;i<=n;i++)
     {
         if (b[i]<0)
          {
              for (j=1;j<=m;j++){c[j]-=a[i][j];a[i][j]=-a[i][j];c[j]+=a[i][j];}
          b[i]=-b[i];
          }
     }
     for (i=1;i<=m;i++)
     {
         if (c[i]<0)
          {for (j=1;j<=n;j++){b[j]-=a[i][j];a[i][j]=-a[i][j];b[j]+=a[i][j];}c[i]=-c[i];}}
     for (i=1;i<=n;i++)s+=b[i];
     for (i=1;i<=m;i++)s+=c[i];
     g<<s;
    f.close();
    g.close();
    return 0;
}