#include <bits/stdc++.h>
#define N 17
using namespace std;

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

int n, m, a[N][N], linie[N], coloana[N], maxim;

void citire(){
    fin>>n>>m;
    for(int i = 1; i <= n; ++i)
        for(int j = 1; j <= m; ++j)
            fin>>a[i][j];
}

void invers(int linie)
{
    for(int j = 1; j <= m; ++j)
        a[linie][j] *= -1;
}

void verif(){
    int sum = 0;
    for(int j=1; j <= m; ++j){
        int sumc = 0;
        for(int i=1; i<=n; ++i)
            sumc += a[i][j];
        if(sumc < 0)
            sumc=-sumc;
        sum += sumc;
    }
    maxim = max(maxim,sum);
}

void Backtracking(int pos)
{
    if(pos == n+1){
        verif();
    } else {
        invers(pos);
        Backtracking(pos+1);
        invers(pos);
        Backtracking(pos+1);
    }
}

int main(){
    citire();
    Backtracking(1);
    fout<<maxim;
}