Problem: Now it's time of Olympiads. Vanya and Egor decided to make his own team to take part in a programming Olympiad. They've been best friends ever since primary school and hopefully, that can somehow help them in teamwork.

For each team Olympiad, Vanya takes his play cards with numbers. He takes only the cards containing numbers 1 and 0. The boys are very superstitious. They think that they can do well at the Olympiad if they begin with laying all the cards in a row so that:

  * there wouldn't be a pair of any side-adjacent cards with zeroes in a row; 
  * there wouldn't be a group of three consecutive cards containing numbers one. 



Today Vanya brought n cards with zeroes and m cards with numbers one. The number of cards was so much that the friends do not know how to put all those cards in the described way. Help them find the required arrangement of the cards or else tell the guys that it is impossible to arrange cards in such a way.

Input

The first line contains two integers: n (1 ≤ n ≤ 106) — the number of cards containing number 0; m (1 ≤ m ≤ 106) — the number of cards containing number 1.

Output

In a single line print the required sequence of zeroes and ones without any spaces. If such sequence is impossible to obtain, print -1.

Examples

Input

1 2


Output

101


Input

4 8


Output

110110110101


Input

4 10


Output

11011011011011


Input

1 5


Output

-1

Solution (in JAVA):

Solution:
import java.io.*;
import java.math.BigInteger; 
import java.util.*;

//Mann Shah [ DAIICT ].
//fast io

public class Main {
	static int mod = (int) (1e9+7);
	static InputReader in;
    static PrintWriter out;
    
   
	public static void main(String args[] )  {
			
		in = new InputReader(System.in);
	    out = new PrintWriter(System.out);
	  
	    int n = in.nextInt();
	    int m = in.nextInt();
	    int t,k;
	    int[] a = new int[3000001];
	    if (n - 1 <= m && m <= 2*(n + 1))
	    {
	        if (m == n - 1) {
	            a[0] = -1;
	            a[m + 1] = -1;
	            t = n - 1;
	        }
	        else if (m == n)
	        {
	            a[m + 1] = -1;
	            t = n;
	        }
	        else t = n + 1;
	        k = m % t;
	        if (k == 0 && m != t) k = n + 1;
	        if (a[0] == -1) out.print("0");
	        for (int i = 1; i <= n; i++)
	        {
	            if (a[i] != -1){
	            if (k > 0) out.print("110");
	            else out.print("10");
	            k--;
	            }
	        }
	        if (a[m + 1] != -1) {
	            if (k > 0) out.println("11");
	            else out.println("1");
	        }
	    }
	    else out.println("-1");
	    
	    
	    
	    out.close();
	}
		
/* TC space



 */
		
		static class InputReader
	    {

	        private final InputStream stream;
	        private final byte[] buf = new byte[8192];
	        private int curChar, snumChars;
	        private SpaceCharFilter filter;

	        public InputReader(InputStream stream)
	        {
	                this.stream = stream;
	        }

	        public int snext()
	        {
	                if (snumChars == -1)
	                        throw new InputMismatchException();
	                if (curChar >= snumChars)
	                {
	                        curChar = 0;
	                        try
	                        {
	                                snumChars = stream.read(buf);
	                        } catch (IOException e)
	                        {
	                                throw new InputMismatchException();
	                        }
	                        if (snumChars <= 0)
	                                return -1;
	                }
	                return buf[curChar++];
	        }

	        public int nextInt()
	        {
	                int c = snext();
	                while (isSpaceChar(c))
	                {
	                        c = snext();
	                }
	                int sgn = 1;
	                if (c == '-')
	                {
	                        sgn = -1;
	                        c = snext();
	                }
	                int res = 0;
	                do
	                {
	                        if (c < '0' || c > '9')
	                                throw new InputMismatchException();
	                        res *= 10;
	                        res += c - '0';
	                        c = snext();
	                } while (!isSpaceChar(c));
	                return res * sgn;
	        }

	        public long nextLong()
	        {
	                int c = snext();
	                while (isSpaceChar(c))
	                {
	                        c = snext();
	                }
	                int sgn = 1;
	                if (c == '-')
	                {
	                        sgn = -1;
	                        c = snext();
	                }
	                long res = 0;
	                do
	                {
	                        if (c < '0' || c > '9')
	                                throw new InputMismatchException();
	                        res *= 10;
	                        res += c - '0';
	                        c = snext();
	                } while (!isSpaceChar(c));
	                return res * sgn;
	        }

	        public int[] nextIntArray(int n)
	        {
	                int a[] = new int[n];
	                for (int i = 0; i < n; i++)
	                {
	                        a[i] = nextInt();
	                }
	                return a;
	        }

	        public long[] nextLongArray(int n)
	        {
	                long a[] = new long[n];
	                for (int i = 0; i < n; i++)
	                {
	                        a[i] = nextLong();
	                }
	                return a;
	        }
	        
	        public ArrayList<Integer> nextArrayList(int n){
	        			ArrayList<Integer> x = new ArrayList<Integer>();
	        			for(int i=0;i<n;i++) {
	        				int v = in.nextInt();
	        				x.add(v);
	        			}
	        			return x;
	        }

	        public String readString()
	        {
	                int c = snext();
	                while (isSpaceChar(c))
	                {
	                        c = snext();
	                }
	                StringBuilder res = new StringBuilder();
	                do
	                {
	                        res.appendCodePoint(c);
	                        c = snext();
	                } while (!isSpaceChar(c));
	                return res.toString();
	        }

	        public String nextLine()
	        {
	                int c = snext();
	                while (isSpaceChar(c))
	                        c = snext();
	                StringBuilder res = new StringBuilder();
	                do
	                {
	                        res.appendCodePoint(c);
	                        c = snext();
	                } while (!isEndOfLine(c));
	                return res.toString();
	        }

	        public boolean isSpaceChar(int c)
	        {
	                if (filter != null)
	                        return filter.isSpaceChar(c);
	                return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
	        }

	        private boolean isEndOfLine(int c)
	        {
	                return c == '\n' || c == '\r' || c == -1;
	        }

	        public interface SpaceCharFilter
	        {
	                public boolean isSpaceChar(int ch);
	        }

	    }
		
}



//Pair arr[] = new Pair[n]; 
//arr[0] = new Pair(10, 20); 
 class Pair { 
    int x; 
    int y; 
  
    // Constructor 
public Pair(int x, int y) 
    { 
        this.x = x; 
        this.y = y; 
    } 
} 
// class Compare { 
//	  //void return by default.
//    static Pair[] compare(Pair arr[], int n) 
//    { 
//        // Comparator to sort the pair according to first element.
//        Arrays.sort(arr, new Comparator<Pair>() { 
//            @Override public int compare(Pair p1, Pair p2) 
//            { 
//                return p1.x - p2.x; 
//            } 
//        }); 
//        
//        
//        return arr;
//       /* for (int i = 0; i < n; i++) { 
//            System.out.print(arr[i].x + " " + arr[i].y + " "); 
//        } 
//        System.out.println(); */
//    } 
//} 




class couple implements Comparable<couple>
{ int x,y;
  public couple(int m,int f) {
 	 x=m;
 	 y=f;
  }
	public int compareTo(couple o) {
		
		 
		return x-o.x;
	}  
}