import sys from collections import deque R, C = map(int, sys.stdin.readline().split()) sy, sx = map(int, sys.stdin.readline().split()) gy, gx = map(int, sys.stdin.readline().split()) start_y = sy - 1 start_x = sx - 1 goal_y = gy - 1 goal_x = gx - 1 grid = [] for _ in range(R): grid.append(sys.stdin.readline().strip()) distance = [[-1 for _ in range(C)] for _ in range(R)] queue = deque() distance[start_y][start_x] = 0 if start_y == goal_y and start_x == goal_x: print(0) sys.exit() queue.append((start_y, start_x)) directions = [(-1, 0), (1, 0), (0, -1), (0, 1)] found = False while queue: y, x = queue.popleft() current_dist = distance[y][x] for dy, dx in directions: ny = y + dy nx = x + dx if 0 <= ny < R and 0 <= nx < C: if grid[ny][nx] == '.' and distance[ny][nx] == -1: distance[ny][nx] = current_dist + 1 if ny == goal_y and nx == goal_x: print(distance[ny][nx]) found = True break queue.append((ny, nx)) if found: break