#include<cstdio>
using namespace std;


int n,m,s,a[17][17],inter[17][17],S[50];


void Solve(int k)
{int i,j,r=0,S1,S2;

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

    for(j=1;j<=k;j++)
    for(i=1;i<=n;i++)
    inter[i][S[j]] = -inter[i][S[j]];

    for(i=1;i<=n;i++)
    {
       S1=0;
        S2=0;
        for(j=1;j<=m;j++)
        {
            S1=S1+inter[i][j];
            S2=S2-inter[i][j];
        }
        if(S1>S2)
        r+=S1;
        else r+=S2;
    }
    if(r>s)
    s=r;
}


void Backtrack (int k)
{
Solve(k-1);
    for(int i=1+S[k-1];i<=m;i++)
    {
        S[k]=i;
        Backtrack(k+1);
    }
}


int main()
{
    int i,j;
    freopen("flip.in","r",stdin);
    freopen("flip.out","w",stdout);
    scanf("%d %d",&n,&m);
    for(i=1;i<=n;i++)
        for(j=1;j<=m;j++)
            scanf("%d",&a[i][j]);
            fclose(stdin);
    Backtrack(1);
    printf("%d",s);
    fclose(stdout);
return 0;
}