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

#define rep(i, n) for (int i = 0; i < (int)n; i++)
using ll = long long int;
using vi = vector<int>;
using vvi = vector<vi>;
using pii = pair<int, int>;
#define INF 1000000001

bool comp(int a, int b) {
  return a > b;
}

int main() {
  int H, W;
  cin >> H >> W;
  vvi A(H, vi (W));
  vvi color(H, vi (W, -1));
  rep(i, H) rep(j, W)
    cin >> A[i][j];
  color[0][0] = 1;
  color[H-1][W-1] = 0;
  pii s = {0, 0};
  pii t = {H-1, W-1};
  vector<int> dx = {0, 1, 0, -1};
  vector<int> dy = {1, 0, -1, 0};
  auto f = [&](int x, int y, int i) {
   return (x + dx[i] >= 0 && x + dx[i] < H &&
	   y + dy[i] >= 0 && y + dy[i] < W);
  };
  auto f2 = [&](int x, int y, set<pair<int, pii>> &v) {
    rep(i, 4) {
      if (!f(x, y, i))
	continue;
      int x1 = x + dx[i];
      int y1 = y + dy[i];
      if (color[x1][y1] != -1)
	continue;
      v.insert({A[x1][y1], {x1, y1}});
    }
  };
  auto f3 = [&](int x, int y, int n) {
    rep(i, 4) {
      if (!f(x, y, i)) continue;
      if (color[x + dx[i]][y + dy[i]] == n)
	return true;
    }
    return false;
  };
  set<pair<int, pii>> sv, tv;
  int i = 0;
  while (1) {
    if (i % 2 == 0) {
      f2(s.first, s.second, sv);
      auto it = sv.begin();
      s = it->second;
      sv.erase(it);
      color[s.first][s.second] = 1;
      i++;
      if (f3(s.first, s.second, 0))
	break;
    } else {
      f2(t.first, t.second, tv);
      auto it = tv.begin();
      t = it->second;
      tv.erase(it);
      color[t.first][t.second] = 0;
      i++;
      if (f3(t.first, t.second, 1))
	break;
    }
  }
  cout << i << endl;
  return 0;
}