#include <fstream>
#include <stdlib.h>
using namespace std;
int main()
{
    ifstream f("flip.in");
    ofstream g("flip.out");
    int m,n,i,j;
    f>>n>>m;
    int long a[n+1][m+1];
    int long long S1,S2;
    for(i=1;i<=n;i++)
        for(j=1;j<=m;j++)
    {
        f>>a[i][j];
    }
    for(i=1;i<=n;i++)
      {
          S1=0;
          S2=0;
    for(j=1;j<=m;j++)
    {
        if (a[i][j]>0) S1=S1+a[i][j];
        else S2=S2+a[i][j];
    }
    //daca S1<abs(S2) atunci comutam
      if(S1<abs(S2)) for(j=1;j<=m;j++) a[i][j]=a[i][j]*(-1);
      }
    for(i=1;i<=m;i++)
      {
          S1=0;
          S2=0;
    for(j=1;j<=n;j++)
    {
        if (a[j][i]>0) S1=S1+a[j][i];
        else S2=S2+a[j][i];
    }
    //daca S1<abs(S2) atunci comutam
      if(S1<abs(S2)) for(j=1;j<=n;j++) a[j][i]=a[j][i]*(-1);
      }
      S1=0;
      for(i=1;i<=n;i++)
      for(j=1;j<=m;j++)
        S1=S1+a[i][j];
        g<<S1;

}