#include <fstream>
#include <iostream>
using namespace std;
ifstream fin("flip.in");
ofstream fout("flip.out");
long a[17][17],n,m,i,j,s,x,y;
int main()
{
    fin>>n>>m;
    for(i=1;i<=n;i++)
        for(j=1;j<=m;j++)
        {
            fin>>a[i][j];
            if(a[i][j] == 0)
            {
                x = i;
                y = j;
            }
        }
    for(i=1;i<=n;i++)
        for(j=1;j<=m;j++)
        {
            if(i == x)
                a[i][j] = a[i][j]*-1;
            if(j == y)
                a[i][j] = a[i][j]*-1;
        }
    for(i=1;i<=n;i++)
        for(j=1;j<=m;j++)
             s+=a[i][j];
    fout<<s;
    return 0;
}