#include <fstream>
#include <iostream>
using namespace std;
ifstream f("flip.in");
ofstream g("flip.out");

int main(){

    short int n,m,i,j;
    long A[18][18];
    long long s,s1;

    f>>n>>m;
    for (i=1;i<=n;i++)
    {
        s=0;
        for (j=1;j<=m;j++){
            f>>A[i][j];
            s+=A[i][j];
        }
        A[i][m+1]=s;
    }
    f.close();

    for (i=1;i<=n;i++){
        if (A[i][m+1]<0){
            for (j=1;j<=m;j++){
                A[i][j]*=-1;
            }
            A[i][m+1]*=-1;
        }
    }

    for (j=1;j<=m;j++){
        s=0;
        for (i=1;i<=n;i++){
            s+=A[i][j];
        }
        A[n+1][j]=s;
        if (s<0){
            for (i=1;i<=n;i++){
                A[i][j]*=-1;
            }
            A[n+1][j]*=-1;
        }
    }

    s1=0;
    for (i=1;i<=n;i++)
        for (j=1;j<=m;j++)
            s1+=A[i][j];
    g<<s1<<"\n";
    g.close();


    return 0;
}