import java.util.Scanner;
import java.util.HashSet;
import java.awt.Point;
class Main{
	private static final int[] dx = {1,-1,0,0};
	private static final int[] dy = {0,0,1,-1};
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		int H = sc.nextInt();
		int W = sc.nextInt();
		int Si = sc.nextInt();
		int Sj = sc.nextInt();
		int Gi = sc.nextInt();
		int Gj = sc.nextInt();
		int ans = dfs(Si,Sj,Gi,Gj,H,W,new HashSet<>());
		System.out.println(ans);
	}
	private static int dfs(int x,int y,int gx,int gy,int H,int W,HashSet<Point> set){
		int count = 0;
		for(int i=0;i<4;i++){
			int nx = x+dx[i];
			int ny = y+dy[i];
			if(set.contains(new Point(nx,ny)))
				count++;
		}
		if(count>1)
			return 0;
		if(x==gx&&y==gy)
			return 1;
		Point p = new Point(x,y);
		set.add(p);
		int ans = 0;
		for(int i=0;i<4;i++){
			int nx = x+dx[i];
			int ny = y+dy[i];
			if(0<nx&&nx<=H&&0<ny&&ny<=W&&!set.contains(new Point(nx,ny)))
				ans += dfs(nx,ny,gx,gy,H,W,set);
		}
		set.remove(p);
		return ans;
	}
}