#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using ld = long double;
using mint = modint998244353;

int H, W, ans = -1, ans2 = -1;
int dx[8] = {-1, 0, 0, 1, -1, -1, 1, 1};
int dy[8] = {0, -1, 1, 0, -1, 1, -1, 1};

int main() {
  cin >> H >> W;
  vector<vector<int>> A(H + 2, vector<int>(W + 2));
  set<vector<vector<int>>> AA;
  for (int i = 1; i <= H; i++) {
    for (int j = 1; j <= W; j++) {
      cin >> A[i][j];
    }
  }
  auto B = A;
  for (int i = 0; i <= H + 1; i++) {
    for (int j = 0; j <= W + 1; j++) {
      if (1 <= i && i <= H && (j != 0 && j != W + 1)) continue;
      if (1 <= j && j <= W && (i != 0 && i != H + 1)) continue;
      //cout << i << ' ' << j << endl;
      for (int k = 0; k < 8; k++) {
        B = A;
        int sum = 0;
        int ni = i + dx[k];
        int nj = j + dy[k];
        while (1 <= ni && ni <= H && 1 <= nj && nj <= W) {
          sum += B[ni][nj];
          B[ni][nj] = 0;
          ni += dx[k];
          nj += dy[k];
        }
        if (sum != 0 && ans <= sum) {
          ans = sum;
          if (ans < sum) AA.clear();
          AA.insert(B);
        }
      }
    }
  }
  for (set<vector<vector<int>>>::iterator it = AA.begin(); it != AA.end(); it++) {
    auto C = *it;
    //for (int i = 1; i <= H; i++) for (int j = 1; j <= W; j++) cout << C[i][j] << " \n"[j == W];
    for (int i = 0; i <= H + 1; i++) {
      for (int j = 0; j <= W + 1; j++) {
        if (1 <= i && i <= H && (j != 0 && j != W + 1)) continue;
        if (1 <= j && j <= W && (i != 0 && i != H + 1)) continue;
        for (int k = 0; k < 8; k++) {
          B = C;
          int sum = 0;
          int ni = i + dx[k];
          int nj = j + dy[k];
          while (1 <= ni && ni <= H && 1 <= nj && nj <= W) {
            sum += B[ni][nj];
            ni += dx[k];
            nj += dy[k];
          }
          if (sum != 0 && ans2 < sum) {
            ans2 = sum;
          }
        }
      }
    }
  }
  //cout << ans << endl;
  cout << ans + ans2 << endl;
  return 0;
}