#include <iostream>
#include <fstream>
using namespace std;
ifstream f("flip.in");
ofstream g("flip.out");
int main()
{
    int n,m,mx=0,a[20][20],b=0,c=0;;
    f>>n>>m;
    for(int o=1;o<=n*m;o++){
    for(int i=1;i<=n;i++){b=0;c=0;
        for(int j=1;j<=m;j++)
        {f>>a[i][j];b+=a[i][j];c-=a[i][j];}

        if(c>b)for(int j=1;j<=m;j++)a[i][j]=-a[i][j];
    }

    for(int j=1;j<=m;j++){b=0;c=0;
        for(int i=1;i<=n;i++)
        {f>>a[i][j];b+=a[i][j];c-=a[i][j];}

        if(c>b)for(int i=1;i<=n;i++)a[i][j]=-a[i][j];
    }
    }
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){mx+=a[i][j];}/*g<<a[i][j]<<" ";}g<<endl;*/}
        g<<mx;
}