#include <iostream> #include <fstream> using namespace std;
ifstream f("flip.in"); ofstream g("flip.out");
int N,M,a[16][16];
int sr(int r){int j,sr=0; for(j=1;j<=M;j++)sr+=a[j][r];;if(-sr>sr){sr*=-1;for(j=1;j<=M;j++)a[j][r]*=-1;}return sr;}
int sc(int c){int j,sc=0; for(j=1;j<=N;j++)sc+=a[c][j];if(-sc>sc){sc*=-1;for(j=1;j<=N;j++)a[c][j]*=-1;}return sc;}

int main()
{
    int s=0,x,y,i;
    f>>N>>M;
    //N=y M=x
    for(i=1;i<=N*M;i++){
        x=i%M; y=i/M;
        if(x==0){x=M;}
        if(i%M!=0){y++;}
        f>>a[x][y];
    }
    for(i=1;i<=N;i++){sr(i);}
    for(i=1;i<=M;i++){sc(i);}
    for(i=1;i<=N*M;i++){
        x=i%M; y=i/M;
        if(x==0){x=M;}
        if(i%M!=0){y++;}
        s+=a[x][y];}
        g<<s;
    f.close();
    g.close();
}

//if(i%M==0)cout<<a[x][y]<<endl;
        //else cout<<a[x][y]<<" ";