/* -*- coding: utf-8 -*-
 *
 * 124.cc: No.124 門松列(3) - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MAX_W = 100;
const int MAX_H = 100;

const int INF = 1 << 30;
const int dxs[] = {1, 0, -1, 0}, dys[] = {0, -1, 0, 1};

/* typedef */

struct Stat {
  int x, y, a;
  Stat() {}
  Stat(int _x, int _y, int _a): x(_x), y(_y), a(_a) {}
};

/* global variables */

int flds[MAX_H][MAX_W], dists[MAX_H][MAX_W][10];

/* subroutines */

/* main */

int main() {
  int w, h;
  cin >> w >> h;

  for (int y = 0; y < h; y++)
    for (int x = 0; x < w; x++) {
      cin >> flds[y][x];
      for (int a = 0; a < 10; a++) dists[y][x][a] = INF;
    }

  queue<Stat> q;

  if (flds[0][0] != flds[0][1])
    q.push(Stat(1, 0, flds[0][0])), dists[0][1][flds[0][0]] = 1;
  if (flds[0][0] != flds[1][0])
    q.push(Stat(0, 1, flds[0][0])), dists[1][0][flds[0][0]] = 1;

  int mind = INF;
  while (! q.empty()) {
    Stat u = q.front(); q.pop();
    int ud = dists[u.y][u.x][u.a];
    if (u.x == w - 1 && u.y == h - 1) {
      mind = ud;
      break;
    }

    int &b = flds[u.y][u.x];
    int vd = ud + 1;
    
    for (int di = 0; di < 4; di++) {
      int vx = u.x + dxs[di], vy = u.y + dys[di];
      if (vx >= 0 && vx < w && vy >= 0 && vy < h) {
	int &c = flds[vy][vx];
	if (c != u.a && ((u.a < b && b > c) || (u.a > b && b < c)) &&
	    dists[vy][vx][b] > vd) {
	  dists[vy][vx][b] = vd;
	  q.push(Stat(vx, vy, b));
	}
      }
    }
  }

  printf("%d\n", mind >= INF ? -1 : mind);
  return 0;
}