import java.util.*; public class Main { private static int ROWS = 1001; public static void main(String[] args) { Scanner sc = new Scanner(System.in); int r = sc.nextInt(); int c = sc.nextInt(); int sy = sc.nextInt() - 1, sx = sc.nextInt() - 1; int gy = sc.nextInt() - 1, gx = sc.nextInt() - 1; char[][] grid = new char[r][c]; for(int i = 0; i < r; i++) grid[i] = sc.next().toCharArray(); int steps = 0; Queue queue = new LinkedList<>(); queue.offer(sx * ROWS + sy); Set visited = new HashSet<>(); visited.add(sx * ROWS + sy); int[] rows = new int[]{-1, 1, 0, 0}; int[] cols = new int[]{0, 0, -1, 1}; while(!queue.isEmpty()) { int size = queue.size(); for(int i = 0; i < size; i++) { int pos = queue.poll(); int col = pos / ROWS; int row = pos % ROWS; if(col == gx && row == gy) { System.out.println(steps); return; } for(int j = 0; j < rows.length; j++) { int nextRow = row + rows[j]; int nextCol = col + cols[j]; if(!isValid(grid, visited, nextRow, nextCol)) continue; queue.offer(nextCol * ROWS + nextRow); visited.add(nextCol * ROWS + nextRow); } } steps++; } } private static boolean isValid(char[][] grid, Set visited, int row, int col) { if(row < 0 || row >= grid.length || col < 0 || col >= grid[0].length || visited.contains(col * ROWS + row) || grid[row][col] == '#') return false; return true; } }