#include<iostream>
#include<fstream>
using namespace std;

ifstream f("flip.in");
ofstream g("flip.out");

int main()
{
    int m,n,Map[20][20],i,j,s1,s2,s=0;
    f>>n>>m;
    for(i=1;i<=n;++i)
        for(j=1;j<=m;++j)
            f>>Map[i][j];
    for(i=1;i<=n;++i)
    {
        s1=0;
        s2=0;
        for(j=1;j<=m;++j)
        {
            if(Map[i][j]>0)s1=s1+Map[i][j];
            else s2=s2-Map[i][j];
        }
        if(s2>s1)
            for(j=1;j<=m;j++)
                Map[i][j]=Map[i][j]*-1;
    }
    for(j=1;j<=m;++j)
    {
        s1=0;
        s2=0;
        for(i=1;i<=n;++i)
        {
            if(Map[i][j]>0)s1=s1+Map[i][j];
            else s2=s2-Map[i][j];
        }
        if(s2>s1)s=s+s2-s1;
        else s=s+s1-s2;
    }
    g<<s;
    return 0;
}