fn solve() -> i64 {
  let hw: Vec<usize> = input().split_whitespace().map(|x| x.parse().unwrap()).collect();
  let h = hw[0];
  let w = hw[1];
  let a: Vec<Vec<i64>> = (0..h).map(|_| {
    input().split_whitespace().map(|x| x.parse().unwrap()).collect()
  }).collect();
  let mut ans = 0;
  let mut outer = vec![(0, 0), (h + 1, 0), (0, w + 1), (h + 1, w + 1)];
  for i in 1..=h {
    outer.push((i, 0));
    outer.push((i, w + 1));
  }
  for j in 1..=w {
    outer.push((0, j));
  }
  let outer = outer;
  let dir = [(-1, 0), (1, 0), (0, 1), (0, -1), (-1, 1), (1, 1), (-1, -1), (1, -1)];
  for &(ox1, oy1) in outer.iter() {
    for &(dx1, dy1) in dir.iter() {
      let mut score1 = 0;
      let mut px = ox1;
      let mut py = oy1;
      let mut placed = vec![vec![true; w]; h];
      loop {
        px = px.saturating_add_signed(dx1).min(h + 1);
        py = py.saturating_add_signed(dy1).min(w + 1);
        if px == 0 || px == h + 1 || py == 0 || py == w + 1 { break; }
        score1 += a[px-1][py-1];
        placed[px-1][py-1] = false;
      }
      for &(ox2, oy2) in outer.iter() {
        for &(dx2, dy2) in dir.iter() {
          let mut score2 = score1;
          px = ox2;
          py = oy2;
          loop {
            px = px.saturating_add_signed(dx2).min(h + 1);
            py = py.saturating_add_signed(dy2).min(w + 1);
            if px == 0 || px == h + 1 || py == 0 || py == w + 1 { break; }
            if placed[px-1][py-1] { score2 += a[px-1][py-1]; }
          }
          ans = ans.max(score2);
        }
      }
    }
  }
  return ans;
}

fn input() -> String {
  let mut buffer = String::new();
  std::io::stdin().read_line(&mut buffer).unwrap();
  return buffer.trim().to_string();
}

fn main() {
  println!("{}", solve());
}