#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
ll n, m, suma, A[20][20], B[20][20];

ifstream fin("flip.in");
ofstream fout("flip.out");

void schimbc(int e){
    for(int i=1; i<=n; i++){
        B[i][e] = -A[i][e];
    }
}

void schimbr(int r){
    for(int i=1; i<=m; i++){
        B[r][i] = -A[r][i];
    }
}

void rind(){
    ll sum1 = 0, sum2 = 0;
    for(int i=1; i<=n; i++){
        for(int j=1; j<=m; j++){
            if(B[i][j] >= 0){
                sum1+=B[i][j];
            } else {
                sum2+= -B[i][j];
            }
        }

        // cout << "suma1 = " << sum1 << endl << "suma 2 = " << sum2 << endl;
        if(sum2 > sum1){
            // cout << "schimb randul " << i << endl;
            schimbr(i);
        }

        sum2 = 0, sum1 = 0;
    }
}

void rsp(){
    for(int i=1; i<=n; i++){
        for(int j=1; j<=m; j++){
            // cout << B[i][j] << ' ';
            suma+=B[i][j];
        }
        // cout << endl;
    }
}

void reschimb(){
    for(int i=1; i<=n; i++){
        for(int j=1; j<=m; j++){
            B[i][j] = A[i][j];
        }
    }
}


int main(){
    fin >> n >> m;

    for(int i=1; i<=n; i++){
        for(int j=1; j<=m; j++){
            fin >> A[i][j];
            B[i][j] = A[i][j];
        }
    }

    ll rs = -1e9;
    for(int b=1; b<(1<<m); b++){
        for(int i=0; i<m; i++){
            if((1<<i) & b){
                // cout << "schimb coloana " << i+1 << endl;
                schimbc(i+1);
            }
        }

        rind();
        rsp();
        if(suma > rs){
            rs = suma;
        }
        suma = 0;
        reschimb();
    }

    fout << rs << endl;

    return 0;
}