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

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

const int NMAX = 16 + 5;
int n, m, ans = 0;
int mat[NMAX][NMAX], prod[NMAX];

inline void backtracking(int k)
{
    if(k != n + 1)
    {
        prod[k] = 1;
        backtracking(k + 1);
        prod[k] = -1;
        backtracking(k + 1);
    }
    else
    {
        int f_sum = 0;
        for(int i = 1; i <= n; ++ i)
        {
            int sum = 0;
            for(int j = 1; j <= m; ++ j)
            {
                sum += prod[j] * mat[i][j];
            }
            if(sum < 0)
                sum*=-1;
            f_sum+=sum;
        }
        ans = max(ans, f_sum);
    }
}

int main()
{
    ios::sync_with_stdio(0);
    cin.tie(NULL);
    cout.tie(NULL);
    fin >> n >> m;
    for(int i = 1; i <= n; ++ i)
    {
        for(int j = 1; j <= m; ++ j)
        {
            fin >> mat[i][j];
            ans+=mat[i][j];
        }
    }
    backtracking(1);
    fout << ans;
}