//
//  main.cpp
//  infoarena
//
//  Created by Darius-George Oanea on 01/03/2019.
//  Copyright © 2019 Darius-George Oanea. All rights reserved.
//

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

//ifstream f("/Users/george/Library/Autosave Information/infoarena/infoarena/en.lproj/adunare.in");
//ofstream g("/Users/george/Library/Autosave Information/infoarena/infoarena/adunare.out");
ifstream f("flip.in");
ofstream g("flip.out");
int main()
{
    int sum = 0;
    int n,m;
    f>>n>>m;
    int a[n][m];
    for(int i=0;i<n;++i)
        for(int j=0;j<m;++j)
        {
            f>>a[i][j];
        }
    
    for(int i=0;i<n;++i)
    {int sum1=0;
        int sum2=0;
        for(int j=0;j<m;++j)
        {
            sum1+= a[i][j] * -1;
            sum2+= a[i][j];
            if(sum1>sum2)
            {
                a[i][j]*=-1;
            }
            
        }
    }
    for(int j=0;j<n;++j)
    {   int sum1=0;
        int sum2=0;
        for(int i=0;i<m;++i)
        {
            sum1+= a[i][j] * -1;
            sum2+= a[i][j];
            if(sum1>sum2)
            {
                a[i][j]*=-1;
            }
            
        }
    }
    
    for(int i=0;i<n;++i)
        for(int j=0;j<m;++j)
        {
            sum+=a[i][j];
        }
    
    g<< sum;
}