#include<fstream>
using namespace std;
ifstream fin("flip.in");
ofstream fout("flip.out");
int n,m,a[20][20],v[20],maxim,sum,i,j,s,b[20][20];
int main()
{
    maxim=-1;
    fin>>n>>m;
    for(i=1;i<=n;i++)
        for(j=1;j<=m;j++)
            fin>>a[i][j];
    while(v[0]==0)
	{
        i=m;
        while(v[i]==1)
		{
            v[i]=0;
            i--;
        }
        v[i]=1;
        for(i=1;i<=n;i++)
		{
            for(j=1;j<=m;j++)
			{
                if(v[j]==1)
                    b[i][j]=-a[i][j];
                else
                    b[i][j]=a[i][j];
            }
        }
        sum=0;
        for(i=1;i<=n;i++)
		{
            s=0;
            for(j=1;j<=m;j++)
                s=s+b[i][j];
            if(s<0)
                sum-=s;
            else
                sum+=s;
        }
        if(sum>maxim)
            maxim=sum;
    }
    fout<<maxim;
    return 0;
}