#include <iostream>
#include <algorithm>
#include <queue>
#include <tuple>
using namespace std;

                            // N  E  S  W
constexpr array<int, 4> dr = {-1, 0, 1, 0},
                        dc = { 0, 1, 0,-1};
constexpr int dr_size = dr.size();

bool is_kado(int a, int b, int c) {
  if(a == 0) { return true; }
  return a!=c && ((a>b&&b<c) || (a<b&&b>c));
}

int main(void) {
  int C, R; scanf("%d%d", &C, &R);
  vector<vector<int>> G(R, vector<int>(C, 0));
  for(int r=0; r<R; ++r) {
    for(int c=0; c<C; ++c) {
      scanf("%d", &G[r][c]);
    }
  }
  vector<vector<vector<vector<bool>>>> seen(R, vector<vector<vector<bool>>>(C, vector<vector<bool>>(10, vector<bool>(10, false)))); // seen[R][C][10][10]
  queue<tuple<int, int, int, int, int>> que;
  que.emplace(0, 0, 0, 0, G[0][0]);
  while(!que.empty()) {
    int cnt, r, c, b2, b1; tie(cnt, r, c, b2, b1) = que.front(); que.pop();
    if(seen[r][c][b2][b1]) { continue; }
    seen[r][c][b2][b1] = true;
    if(r == R-1 && c == C-1) {
      printf("%d\n", cnt);
      return 0;
    }
    for(int i=0; i<dr_size; ++i) {
      int nr = r + dr[i],
          nc = c + dc[i];
      if(!(0 <= nr && nr < R && 0 <= nc && nc < C)) { continue; }
      if(!is_kado(b2, b1, G[nr][nc])) { continue; }
      que.emplace(cnt+1, nr, nc, b1, G[nr][nc]);
    }
  }
  puts("-1");
  return 0;
}