from queue import PriorityQueue

W,H = list(map(int, input().split(' ')))

G = []
for i in range(H):
    G.append(list(map(int, input().split(' '))))

distance = []
for i in range(H):
    for j in range(W):
        distance.append([[float('inf') for _ in range(10)] for _ in range(W)])

def is_kadomatsu(prev,current,next):
    if prev == 0:
        return True
    return ((prev < current and next < current) or (current < prev and current < next)) and prev != next


def dijkstra():
    dx = [1, 0, -1, 0]
    dy = [0, 1, 0, -1]

    que = PriorityQueue()

    que.put((0,0,0,0))
    distance[0][0][0] = 0

    answer = -1
    while not que.empty():
        dist,last,x,y = que.get()
        if x == H-1 and y == W-1:
            answer = dist
            break
        for i in range(len(dx)):
            nx = x + dx[i]
            ny = y + dy[i]
            if 0 <= nx and 0 <= ny and nx < H and ny < W \
               and distance[nx][ny][G[x][y]] == float('inf') \
                   and is_kadomatsu(last, G[x][y], G[nx][ny]):
                que.put((dist+1,G[x][y],nx,ny))
                distance[nx][ny][G[x][y]] = dist+1

    print(answer)

dijkstra()