#include <iostream>
#include <fstream>

using namespace std;

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

long long n, m, s, s1, s2, mn1, mn2, i, j, a[20][20] , imin, jmin;
int main()
{
    fin >> n >> m;
    s = 0;
    s1 = 0;
    s2 = 0;
    mn1 = 0;
    mn2 = 0;
    imin = 1;
    jmin = 1;

    for(i = 1; i <= n; i++)
        for(j = 1; j <= m; j++)
            fin >> a[i][j];


    for(j = 1; j <= m; j++)
        mn1 = mn1 + a[1][j];
    for(i = 1; i <= n; i++)
        mn2 = mn2 + a[i][1];


    for(i = 2; i <= n; i++)
        { s1 = 0;
            for(j = 1; j <= m; j++)
                s1 = s1 + a[i][j];
            if(s1 < mn1)
               {
                mn1 = s1;
                imin = i;
               }
               s1 = 0;
        }
    for(j = 2; j <= m; j++)
    {
        for(i = 1; i <= n; i++)
            s2 = s2 + a[i][j];
        if(s2 < mn2)
        {
            mn2 = s2;
            jmin = j;
        }
    s2 = 0;
    }

    for(j = 1; j <= m; j++)
       a[imin][j] = a[imin][j] * (-1);
    for(i = 1; i <= n; i++)
       a[i][jmin] = a[i][jmin] * (-1);


for(i = 1; i <= n; i++)
    for(j = 1; j <= m; j++)
       s = s + a[i][j];
  fout << s;

        return 0;
    }