#include <iostream>
#include <fstream>
using namespace std;
int main() {

    ifstream fin("flip.in");
    ofstream fout("flip.out");

    int matrice[16][16], i, j, N, M, linie, coloana;
    fin >> N >> M;
    for(i = 0; i < N; i++)
        for(j = 0; j < M; j++)
            fin>>matrice[i][j];

    int Sum, Sum_minus;


    // Pe linie!!!
    for(i = 0; i < N; i++){
        Sum = 0;
        Sum_minus = 0;
        for(j = 0; j < M; j++){
            Sum+=matrice[i][j];
            Sum_minus+=matrice[i][j]*-1;
        }

        if(Sum_minus > Sum){
            for(linie = i; linie < N; linie++)
                for(coloana = 0; coloana < M; coloana++)
                    matrice[linie][coloana]=matrice[linie][coloana] * -1;
        }

    }

    // Pe coloana !!!

     for(j = 0; j < M; j++){
            Sum = 0;
            Sum_minus = 0;
            for(i = 0; i < N; i++){
            Sum += matrice[i][j];
            Sum_minus = Sum_minus * -1;
        }
        if(Sum_minus > Sum){
            for(coloana = j; coloana < M; coloana++)
                for(linie = 0; linie < N; linie++)
                    matrice[linie][coloana] = matrice[linie][coloana] * -1;
        }
     }
    Sum = 0;
    //Afisare
    for(i = 0; i < N; i++){
        for(j = 0; j < M; j++)
            Sum += matrice[i][j];
    }
    fout << Sum;

    return 0;
}