#include <cstdio>
#include <iostream>

using namespace std;

//------------------------------------------

void citire(int a[][20], int &n, int &m)
{
    scanf("%d %d", &n, &m);
    for(int i = 1; i <= n; i++)
        for(int j = 1; j <= m; j++)
            scanf("%d", &a[i][j]);
}

void afisare(int a[][20], int n, int m)
{
    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= m; j++)
            printf("%d ", a[i][j]);
        printf("\n"); }
    printf("\n");
}

//------------------------------------------

int sumMatrix(int a[][20], int n, int m)
{
    int s = 0;
    for(int i = 1; i <= n; i++)
        for(int j = 1; j <= m; j++)
            s += a[i][j];
    return s;
}

void copyMatrix(int aBest[][20], int a[][20], int n, int m)
{
    for(int i = 1; i <= n; i++)
        for(int j = 1; j <= m; j++)
            aBest[i][j] = a[i][j];
}

//

void xLine(int a[][20], int i, int m)
{
    for(int j = 1; j <= m; j++)
        a[i][j] *= (-1);
}

void xCol(int a[][20], int j, int n)
{
    for(int i = 1; i <= n; i++)
        a[i][j] *= (-1);
}

//

void parcurgere(int aBest[][20], int a[][20], int n, int m, int &sumBest)
{
    for(int i = 1; i <= n; i++)
    {
        xLine(a,i,m);

        for(int j = 1; j <= m; j++)
        {
            xCol(a,j,n);

            if(sumMatrix(a,n,m) > sumBest)
            {
                sumBest = sumMatrix(a,n,m);
                copyMatrix(aBest,a,n,m);
            }

            xCol(a,j,n);
        }

        xLine(a,i,m);
    }
}

//------------------------------------------

int main()
{
    freopen("flip.in", "r", stdin);
    freopen("flip.out", "w", stdout);

    int a[20][20],n,m;
    int aBest[20][20], sumBest;

    sumBest = sumMatrix(a,n,m);

    citire(a,n,m);
    parcurgere(aBest,a,n,m,sumBest);

    printf("%d\n\n", sumBest);

    fclose(stdin),fclose(stdout);
}