static void solve() {
int r = in.nextInt();
int c = in.nextInt();
int sy = in.nextInt() - 1;
int sx = in.nextInt() - 1;
int gy = in.nextInt() - 1;
int gx = in.nextInt() - 1;
char[][] t = new char[r][c];
for (int i = 0; i < r; i++) {
t[i] = in.next().toCharArray();
}
ArrayDeque<int[]> que = new ArrayDeque<>();
BitSet visited = new BitSet();
que.add(new int[] {sy, sx, 0});
visited.set(sy * c + sx);
int[] dx = {0, 1, 0, -1};
int[] dy = {1, 0, -1, 0};
int[][] dist = new int[r][c];
while (!que.isEmpty()) {
int[] p = que.pollFirst();
int cy = p[0];
int cx = p[1];
int d = p[2];
dist[cy][cx] = d;
for (int i = 0; i < 4; i++) {
int ny = cy + dy[i];
int nx = cx + dx[i];
if (ny < 0 || nx < 0 || r <= ny || c <= nx) continue;
if (visited.get(ny * c + nx) || t[ny][nx] == '#') continue;
que.add(new int[] {ny, nx, d + 1});
visited.set(ny * c + nx);
}
}
out.println(dist[gy][gx]);
}
