import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String[] sa = br.readLine().split(" ");
		int r = Integer.parseInt(sa[0]);
		int c = Integer.parseInt(sa[1]);
		sa = br.readLine().split(" ");
		int sy = Integer.parseInt(sa[0]);
		int sx = Integer.parseInt(sa[1]);
		sa = br.readLine().split(" ");
		int gy = Integer.parseInt(sa[0]);
		int gx = Integer.parseInt(sa[1]);
		char[][] a = new char[r][c];
		for (int i = 0; i < a.length; i++) {
			a[i] = br.readLine().toCharArray();
		}
		br.close();

		System.out.println(Math.abs(gy - sy) + Math.abs(gx - sx));
	}
}