#include <bits/stdc++.h>
#define for0(i, n) for(int i = 0; i < n; i++)
#define for1(i, n) for(int i = 1; i <= n; i++)
#define pb push_back
#define mp make_pair
#define all(v) v.begin(), v.end()
#define V vector<int>
#define VP vector<pair<int, int> >
#define FASTIO ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
using namespace std;
#ifdef _WIN32
#include <windows.h>
#define print(x) PRINT(x, #x)
template<typename T> inline const void PRINT(T VARIABLE, string NAME)
{
#ifndef ONLINE_JUDGE /// ONLINE_JUDGE IS DEFINED ON CODEFORCES
    HANDLE hConsole = GetStdHandle(STD_OUTPUT_HANDLE);
    SetConsoleTextAttribute(hConsole, 10);
    cerr << NAME << " = " << VARIABLE;
    SetConsoleTextAttribute(hConsole, 7);
    cerr << '\n';
#endif
}
#else
#define print(x) 0
#endif
typedef long long ll;
typedef unsigned long long ull;
const ll INFLL = 2 * (ll)1e18 + 100;
const int INFINT = 2 * (int)1e9 + 100;
const double PI = atan(1) * 4;
const double EPS = 1e-12;
const int SEED = 1e3 + 7;

const int MOD = 1e9 + 7; /// careful here (7 or 9, 66.. etc)
const int NMAX = 1e6 + 5;

ifstream fin("flip.in");
ofstream fout("flip.out");
#define cin fin
#define cout fout

int n, m;
int mat[20][20], sum_pos[20], sum_neg[20];
int sol = -INFINT;

int main()
{
    FASTIO;
    cin >> n >> m;
    for1(i, n) for1(j, m)
    {
        cin >> mat[i][j];
        if(mat[i][j] > 0) sum_pos[j] += mat[i][j];
        else sum_neg[j] -= mat[i][j];
    }

    for(int i = (1 << n) - 1; i >= 0; i--)
    {
        vector<int> s_pos(20), s_neg(20);
        for(int j = 0; j < n; j++) if((i >> j) & 1)
        {
            for1(col, m)
            {
                if(mat[j + 1][col] > 0) s_pos[col] += mat[j + 1][col];
                else s_neg[col] -= mat[j + 1][col];
            }
        }

        int sum = 0;
        for1(j, m)
        {
            sum += max(sum_pos[j] - s_pos[j] + s_neg[j], sum_neg[j] + s_pos[j] - s_neg[j]) -
            min(sum_pos[j] - s_pos[j] + s_neg[j], sum_neg[j] + s_pos[j] - s_neg[j]);
        }
        sol = max(sol, sum);
    }
    cout << sol;
    return 0;
}