#include <iostream>
#include <cstdio>

using namespace std;

long rasp,n,m,v[40],a[20][20];

void suma()
{
    int i,j,sum;
    sum=0;
    for (i=1;i<=n;i++)
        for (j=1;j<=m;j++) if (((v[i]==0) && (v[n+j]==0)) || (v[i]==1) && (v[n+j]==1)) sum=sum+a[i][j];
                            else sum=sum-a[i][j];
    if (sum>rasp) rasp=sum;
}

void subm(int k)
{
    int q;
    for (q=0;q<=1;q++)
    {
        v[k]=q;
        if (k==n+m) suma();
        else subm(k+1);
    }
}

long i,j;

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