#include <iostream>
#include <fstream>
using namespace std;
const int MAX_N = 16, MAX_M = 16;
int a[MAX_N+1][MAX_M+1], v[MAX_N+1][MAX_M+1];
int n, m;
void col(int j)
{
    for(int i = 1; i <= n; i++)
        v[i][j]=-1*v[i][j];
}

int main()
{
    ifstream f("flip.in");
    ofstream g("flip.out");
 f>>n>>m;
    int i, j, k;
    long long s= 0, r = 0;
    long long sln = 0;
    for(i = 1; i <= n; i++)
        for(j = 1; j <= m; j++)
            f>>a[i][j];

    for(i = 0; i < (1 << m); i++)
    {
        s = 0;
        for(j = 1; j <= n; j++)
            for(k  = 1; k <= m; k++)
                v[j][k] = a[j][k];
        for(j = 0; j < m; j++)
            if(i&(1<<j))
                col(j);
        for(j = 1; j <= n; j++)
        {
            sln = 0;
            for(k = 1; k <= m; k++)
                sln = sln+v[j][k];
            if(sln < 0) sln=-1*sln;
            s=s+sln;
        }
        if(s > r)
            r = s;
    }
   g<<r;
    return 0;
}