#include <fstream>
using namespace std;
ifstream f("flip.in");
ofstream g("flip.out");
int m[20][20],i,j,n,l,c,valc,vall,bit,sum,k,rasp;

int verif()
{
    int sum=0,sumc;
    for (int i=0;i<l;++i)
    {
    sumc=0;
    for (int j=0;j<c;++j)
        sumc+=m[i][j];
    sum+=sumc>0?sumc:-sumc;
    }
    return sum;
}
int main()
{
    f>>l>>c;
    for (i=0;i<l;++i)
    for (j=0;j<c;++j)
    f>>m[i][j];

    for (i=1;i<=(1<<c);++i)
    {
        valc=i^(i/2);
        vall=(i-1)^((i-1)/2);
        bit=vall^valc;

        for (j=0;j<=16;++j)
            if (bit==(1<<j))
                break;

        for (k=0;k<l;++k)
            m[k][j]*=-1;

        sum=verif();

        if (sum>rasp)
        rasp=sum;
    }
    g<<rasp;
    return 0;
}