import sys
#sys.setrecursionlimit(n)
import heapq
import re
import bisect
import random
import math
import itertools
from collections import defaultdict, deque
from copy import deepcopy
from decimal import *

w, h = map(int, input().split())
e = [[int(i) for i in input().split()] for _ in range(h)]
v = defaultdict(lambda:defaultdict(lambda:defaultdict(lambda:defaultdict(lambda:defaultdict(lambda:defaultdict(list))))))
def solve():
  q = deque()
  q.append((0 << 48) + (0 << 32) + (0 << 24) + (0 << 16) + (0 << 8) + 0)
  direction = ((0,1),(0,-1),(1,0),(-1,0))
  while(q):
    qq = q.popleft()
    flag = qq >> 48
    qc = (qq >> 32) & 0xFFFF
    qw2 = (qq >> 24) & 0xFF
    qh2 = (qq >> 16) & 0xFF
    qw = (qq >> 8) & 0xFF
    qh = qq & 0xFF
    if qw == (w - 1) and qh == (h - 1):
      return qc
    for ddir in direction:
      dw = ddir[0] + qw
      dh = ddir[1] + qh
      if dw >= w or dh >= h or dw < 0 or dh < 0 or v[dh][dw][qh][qw][qh2][qw2]:
        continue
      if flag:
        v[dh][dw][qh][qw][qh2][qw2] = True
        if (e[dh][dw] != e[qh][qw]) and (e[dh][dw] != e[qh2][qw2]) and (e[qh][qw] != e[qh2][qw2]):
          if (e[dh][dw] > e[qh][qw] and e[qh][qw] < e[qh2][qw2]) or (e[dh][dw] < e[qh][qw] and e[qh][qw] > e[qh2][qw2]):
              q.append((1 << 48) + ((qc + 1) << 32) + (qw << 24) + (qh << 16) + (dw << 8) + dh)
      else:
          q.append((1 << 48) + ((qc + 1) << 32) + (qw << 24) + (qh << 16) + (dw << 8) + dh)
  return -1
print(solve())