#include <bits/stdc++.h>

#define rep(i, n) for (int i = 0; i < int(n); i++)
#define rrep(i, n) for (int i = int(n) - 1; i >= 0; i--)
#define reps(i, n) for (int i = 1; i <= int(n); i++)
#define rreps(i, n) for (int i = int(n); i >= 1; i--)
#define repc(i, n) for (int i = 0; i <= int(n); i++)
#define rrepc(i, n) for (int i = int(n); i >= 0; i--)
#define repi(i, a, b) for (int i = int(a); i < int(b); i++)
#define repic(i, a, b) for (int i = int(a); i <= int(b); i++)
#define all(a) (a).begin(), (a).end()
#define bit32(x) (1 << (x))
#define bit64(x) (1ll << (x))
#define sz(v) ((int) v.size())

using namespace std;

using i64 = long long;
using f80 = long double;
using vi32 = vector<int>;
using vi64 = vector<i64>;
using vf80 = vector<f80>;
using vstr = vector<string>;

inline void yes() { cout << "Yes" << endl; exit(0); }
inline void no() { cout << "No" << endl; exit(0); }
inline i64 gcd(i64 a, i64 b) { if (min(a, b) == 0) return max(a, b); if (a % b == 0) return b; return gcd(b, a % b); }
inline i64 lcm(i64 a, i64 b) { if (min(a, b) == 0) return max(a, b); return a / gcd(a, b) * b; }
template <typename T> class pqasc : public priority_queue<T, vector<T>, greater<T>> {};
template <typename T> class pqdesc : public priority_queue<T, vector<T>, less<T>> {};
template <typename T> inline void amax(T &x, T y) { x = max(x, y); }
template <typename T> inline void amin(T &x, T y) { x = min(x, y); }
template <typename T> inline T exp(T x, i64 n, T e = 1) { T r = e; while (n > 0) { if (n & 1) r *= x; x *= x; n >>= 1; } return r; }
template <typename T> istream& operator>>(istream &is, vector<T> &v) { for (auto &x : v) is >> x; return is; }
template <typename T> ostream& operator<<(ostream &os, vector<T> &v) { rep(i, v.size()) { if (i) os << ' '; os << v[i]; } return os; }
void solve(); int main() { ios::sync_with_stdio(0); cin.tie(0); cout << fixed << setprecision(16); solve(); return 0; }

int dp[100][100][10][10];
int dx[] = {-1, 0, 1, 0};
int dy[] = {0, -1, 0, 1};

void solve() {
  rep(i, 100) rep(j, 100) rep(k, 10) rep(l, 10) {
    dp[i][j][k][l] = 1e9;
  }
  int w, h;
  cin >> w >> h;
  vector<vi32> s(h, vi32(w));
  cin >> s;
  using T = tuple<int, int, int, int, int>;
  queue<T> q;
  q.emplace(0, 0, 0, 0, s[0][0]);
  while (sz(q)) {
    int x, y, cost, a, b;
    tie(x, y, cost, a, b) = q.front();
    q.pop();
    if (dp[x][y][a][b] != 1e9) {
      continue;
    }
    dp[x][y][a][b] = cost;
    rep(i, 4) {
      int nx = x + dx[i];
      int ny = y + dy[i];
      if (nx < 0 || nx >= h || ny < 0 || ny >= w) {
        continue;
      }
      int c = s[nx][ny];
      if (a == 0 && b != c) {
        q.emplace(nx, ny, cost + 1, b, c);
        continue;
      }
      if (a > b && b < c && a != c) {
        q.emplace(nx, ny, cost + 1, b, c);
      } else
      if (a < b && b > c && a != c) {
        q.emplace(nx, ny, cost + 1, b, c);
      }
    }
  }
  int ans = 1e9;
  rep(k, 10) rep(l, 10) {
    amin(ans, dp[h - 1][w - 1][k][l]);
  }
  if (ans == 1e9) ans = -1;
  cout << ans << endl;
}