#include <fstream>
#include <vector>
#include <climits>
#include <cmath>

using namespace std;

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

int a[20][20],n,m,sol = -INT_MAX;
vector<int> coloane;

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

void flip_col(int col){
    for(int lin = 1; lin<=n; lin++)
        a[lin][col]*=-1;
}

void backtracking(int col){
    if(col == m+1){
        int total = 0, sum;
        for(int col : coloane)
            flip_col(col);
        for(int lin = 1; lin <= n; lin++){
            sum = 0;
            for(int j=1; j<=m;j++)
                sum+=a[lin][j];
            total+=abs(sum);
        }
        sol = max(sol, total);
        for(int col : coloane)
            flip_col(col);
        return;
    }
    backtracking(col+1);
    coloane.push_back(col);
    backtracking(col+1);
    coloane.pop_back();
}

int main()
{
    citire();
    backtracking(1);
    fout << sol;
    return 0;
}