#include <bits/stdc++.h>

using namespace std;

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

int main() {
    int n, m;
    in >> n >> m;
    
    vector<vector<int>> v(n, vector<int>(m));
    for (auto& row: v) {
        for (auto& val: row) {
            in >> val;
        }
    }

    vector<bitset<16>> rowMasks;
    for (int i = 0; i < (1 << n); i++) {
        rowMasks.emplace_back(bitset<16>(i));
    }
    vector<bitset<16>> colMasks;
    for (int i = 0; i < (1 << m); i++) {
        colMasks.emplace_back(bitset<16>(i));
    }

    int sol = INT_MIN;
    for (const auto& rowMask: rowMasks) {
        for (const auto& colMask: colMasks) {
            int sum = 0;
            for (int i = 0; i < n; i++) {
                bool rowBit = rowMask[i];
                for (int j = 0; j < m; j++) {
                    bool colBit = colMask[j];
                    int vij = v[i][j];
                    if (rowBit) vij *= -1;
                    if (colBit) vij *= -1;
                    sum += vij;
                }
            }
            sol = max(sol, sum);
        }
    }

    out << sol;

    return 0;
}