#include <bits/stdc++.h>
using namespace std;
#define int long long

void solve()
{
  int rows, cols;
  cin >> rows >> cols;
  vector<vector<int>> c(rows, vector<int>(cols));
  int sum = 0;
  for(int i = 0; i < rows; i++)
    for(int j = 0; j < cols; j++)
    {
      cin >> c[i][j];
      sum += c[i][j];
    }


  if(rows % 2 == 1 || cols % 2 == 1)
  {
    cout << sum << endl;
    return;
  }

  int min_ = 10000;
  for(int i = 0; i < rows; i++)
    for(int j = 0; j < cols; j++)
      if((i + j) % 2 == 1)
        min_ = min(min_, c[i][j]);
  cout << (sum - min_) << endl;
  return;
}

int32_t main()
{
  ios::sync_with_stdio(false);
  cin.tie(0);

  solve();

  return 0;
}