import java.util.Arrays;
import java.util.LinkedList;
import java.util.Scanner;

public class Main {
	
	public static int solve(int X, int Y){
		if(X == Y){ 
			return 0;
		}else if(Y == 0){
			// (X, 0) -> (X, X)
			return 1;
		}else if(X == 0){
			// (0, Y) -> (Y, 0)
			return 1 + solve(Y, 0);
		}else if(Math.abs(X) != Math.abs(Y)){
			return -1;
		}else{
			return solve(X + Y, X - Y);
		}
	}
	
	public static final int INF = Integer.MAX_VALUE / 2 - 1;
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		final int X = sc.nextInt();
		final int Y = sc.nextInt();
		
		final int OFFSET = 200;
		final int SIZE = OFFSET + 1 + OFFSET;
		
		int[][] DP = new int[SIZE][SIZE];
		for(int i = 0; i < SIZE; i++){
			for(int j = 0; j < SIZE; j++){
				DP[i][j] = (i == j) ? 0 : INF;
			}
		}
		
		while(true){
			boolean update = false;
			
			for(int i = 0; i < SIZE; i++){
				for(int j = 0; j < SIZE; j++){
					if(DP[j][i] > DP[i][j] + 1){
						DP[j][i] = DP[i][j] + 1; update = true;
					}
					
					final int y = i - OFFSET;
					final int x = j - OFFSET;
					final int nx = x + y;
					final int ny = x - y;
					
					final int ni = ny + OFFSET;
					final int nj = nx + OFFSET;
					if(ni >= 0 && ni < SIZE && nj >= 0 && nj < SIZE && DP[ni][nj] > DP[i][j] + 1){
						DP[ni][nj] = DP[i][j] + 1; update = true;
					}
				}
			}
			
			if(!update){ break; }
		}
		
		//System.out.println(solve(X, Y));
		System.out.println(DP[Y + OFFSET][X + OFFSET] == INF ? -1 : DP[Y + OFFSET][X + OFFSET]);
	}
}