#include <fstream>
using namespace std;
ifstream f("flip.in");
ofstream g("flip.out");
int m, n, mat[17][17], i, j, l, sbm[17], sl[17], sc[17], s_tmp, cop, smax=-2000000000, conf[17];
int main()
{
    f>>n>>m;
    for (i=1; i<=n; i++)
        for (j=1; j<=m; j++)
        {
            f>>mat[i][j];
            sc[j]+=mat[i][j];
        }

    while (sbm[m+1] == 0)
    {
        s_tmp=0;
        l=1;
        while (sbm[l]==1)
        {
            sbm[l]=0;
            l++;
        }
        sbm[l]=1;
        if (sbm[m+1]==0)
        {
            for (i=1; i<=m; i++)
            {
                if (sbm[i]==1)
                    s_tmp+=sc[i]*-1;
                else
                    s_tmp+=sc[i];
            }
            if (smax < s_tmp)
            {
                smax = s_tmp;
                for (i=1; i<=m; i++)
                    conf[i]=sbm[i];
            }
        }
    }

    for (i=1; i<=m; i++)
    {
        sbm[i]=0;
        if (conf[i]==1)
            for (j=1; j<=n; j++)
                mat[j][i]*=-1;
    }
    sbm[m+1]=0;
    for (i=1; i<=n; i++)
        for (j=1; j<=m; j++)
            sl[i]+=mat[i][j];

    cop=smax;
    while (sbm[n+1] == 0)
    {
        s_tmp=cop;
        l=1;
        while (sbm[l]==1)
        {
            sbm[l]=0;
            l++;
        }
        sbm[l]=1;
        if (sbm[n+1]==0)
        {
            for (i=1; i<=n; i++)
                if (sbm[i]==1)
                    s_tmp+=2*sl[i]*-1;
            if (smax < s_tmp)
                smax = s_tmp;
        }
    }
    g<<smax;
    return 0;
}