from collections import deque

def is_kadomatsu(a, b, c):
    if a == b or b == c or a == c:
        return False
    sorted_vals = sorted([a, b, c], reverse=True)
    mid = sorted_vals[1]
    return mid == a or mid == c

def main():
    import sys
    input = sys.stdin.read().split()
    ptr = 0
    W = int(input[ptr])
    ptr += 1
    H = int(input[ptr])
    ptr += 1
    grid = []
    for y in range(H):
        row = list(map(int, input[ptr:ptr+W]))
        ptr += W
        grid.append(row)
    
    start_x, start_y = 0, 0
    goal_x, goal_y = W-1, H-1
    if start_x == goal_x and start_y == goal_y:
        print(0)
        return
    
    visited = [[[[False for _ in range(10)] for __ in range(10)] for ___ in range(W)] for ____ in range(H)]
    directions = [ (0, 1), (1, 0), (0, -1), (-1, 0) ]
    queue = deque()
    
    initial_val = grid[start_y][start_x]
    for dx, dy in directions:
        new_x = start_x + dx
        new_y = start_y + dy
        if 0 <= new_x < W and 0 <= new_y < H:
            next_val = grid[new_y][new_x]
            if not visited[new_y][new_x][initial_val][next_val]:
                visited[new_y][new_x][initial_val][next_val] = True
                queue.append( (new_x, new_y, initial_val, next_val, 1) )
    
    found = -1
    while queue:
        x, y, pv, cv, steps = queue.popleft()
        if x == goal_x and y == goal_y:
            found = steps
            break
        for dx, dy in directions:
            new_x = x + dx
            new_y = y + dy
            if 0 <= new_x < W and 0 <= new_y < H:
                new_val = grid[new_y][new_x]
                if not is_kadomatsu(pv, cv, new_val):
                    continue
                if not visited[new_y][new_x][cv][new_val]:
                    visited[new_y][new_x][cv][new_val] = True
                    queue.append( (new_x, new_y, cv, new_val, steps + 1) )
    print(found if found != -1 else -1)

if __name__ == '__main__':
    main()