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.util.*;
//_________________________________________________________________
public class Main {


    public static void main(String[] args) throws IOException {


//        File file = new File("input.txt");
        FastScanner sc = new FastScanner();
//                Scanner sc= new Scanner(System.in);
        PrintWriter out = new PrintWriter(System.out);
        int zero=sc.nextInt(),one=sc.nextInt();
        StringBuilder ans= new StringBuilder();
        if (zero-one>1||one>2*(zero+1)){
            System.out.println(-1);
            return;
        }
        boolean f=false;
        if (zero==one+1){
            ans.append("0");
            zero--;
            f=true;
        }
        while (zero>0&&one>0&&zero!=one){
            ans.append("110");
            zero--;
            one-=2;
            f=true;
        }
        if (zero==one){
            if (!f) {
                StringBuilder sb = new StringBuilder();
                for (int i = 0; i < zero; i++) {
                    sb.append("10");
                }
                System.out.println(sb.toString());
                return;
            }
            else{
                for (int i=0;i<zero;i++){
                    ans.append("10");
                }
            }
            System.out.println(ans.toString());
            return;
        }
        while (one>0){
            ans.append("1");
            one--;
        }
        while (zero>0){
            ans.append("0");
            zero--;
        }
        System.out.println(ans.toString());


        out.flush();

    }
    //------------------------------------if-------------------------------------------------------------------------------------------------------------------------------------------------
    //sieve
    static void primeSieve(int a[]){
        //mark all odd number as prime
        for (int i=3;i<a.length;i+=2){
            a[i]=1;
        }
        for (long i=3;i<a.length;i+=2){
            //if the number is marked then it is prime
            if (a[(int) i]==1){
                //mark all muliple of the number as not prime
                for (long j=i*i;j<a.length;j+=i){
                    a[(int)j]=0;
                }
            }
        }
        a[2]=1;
        a[1]=a[0]=0;
    }
    static void sort(int[] a) {
        ArrayList<Integer> l = new ArrayList<>();
        for (int i : a) l.add(i);
        Collections.sort(l);
        for (int i = 0; i < a.length; i++) a[i] = l.get(i);
    }
    static String sortString(String s) {
        char temp[] = s.toCharArray();
        Arrays.sort(temp);
        return new String(temp);
    }
    static class Pair implements Comparable<Pair> {
        int a;
        int b;

        public Pair(int a, int b) {
            this.a = a;
            this.b = b;
        }
        //        to sort first part
//        public int compareTo(Pair other) {
//            if (this.a == other.a) return other.b > this.b ? -1 : 1;
//            else if (this.a > other.a) return 1;
//            else return -1;
//        }
//        public int compareTo(Pair other) {
//            if (this.b == other.b) return 0;
//            if (this.b < other.b) return 1;
//            else return -1;
//        }
        //sort on the basis of first part only
        public int compareTo(Pair other) {
            if (this.a == other.a) return 0;
            else if (this.a > other.a) return 1;
            else return -1;
        }

    }
    static int[] frequency(String s){
        int fre[]= new int[26];
        for (int i=0;i<s.length();i++){
            fre[s.charAt(i)-'a']++;
        }
        return fre;
    }
    static long LOWERBOUND(long a[],long k){
        int s=0,e=a.length-1;
        long ans=-1;
        while (s<=e){
            int mid=(s+e)/2;
            if (a[mid]<=k){
                ans=mid;
                s=mid+1;
            }
            else {
                e=mid-1;
            }
        }
        return ans;
    }
    static int mod =(int)(1e9+7);
    static long mod(long x) {
        return ((x % mod + mod) % mod);
    }
    static long add(long x, long y) {
        return mod(mod(x) + mod(y));
    }
    static long mul(long x, long y) {
        return mod(mod(x) * mod(y));
    }
    //Fast Power(logN)
    static long BinaryExponentiation(long a,long b){
        long ans=1;
        while (b>0){
            if (b%2==1){
                ans=(ans*a)%mod;
            }
            a=(a*a)%mod;
            b/=2;
        }
        return ans;
    }
    static int[] find(int n, int start, int diff) {
        int a[] = new int[n];
        a[0] = start;
        for (int i = 1; i < n; i++) a[i] = a[i - 1] + diff;
        return a;
    }
    static void swap(int a, int b) {
        int c = a;
        a = b;
        b = c;
    }
    static void printArray(int a[]) {
        for (int i = 0; i < a.length; i++) {
            System.out.print(a[i] + " ");
        }
    }
    static boolean sorted(int a[]) {
        int n = a.length;
        boolean flag = true;
        for (int i = 0; i < n - 1; i++) {
            if (a[i] > a[i + 1]) flag = false;
        }
        if (flag) return true;
        else return false;
    }
    public static int findlog(long n) {
        if (n == 0)
            return 0;

        if (n == 1)
            return 0;
        if (n == 2)
            return 1;
        double num = Math.log(n);
        double den = Math.log(2);
        if (den == 0)
            return 0;
        return (int) (num / den);
    }
    public static long gcd(long a, long b) {
        if (b % a == 0)
            return a;
        return gcd(b % a, a);
    }
    public static int gcdInt(int a, int b) {

        if (b % a == 0)
            return a;

        return gcdInt(b % a, a);

    }
    static void sortReverse(int[] a) {
        ArrayList<Integer> l = new ArrayList<>();
        for (int i : a) l.add(i);
        //        Collections.sort.(l);
        Collections.sort(l, Collections.reverseOrder());
        for (int i = 0; i < a.length; i++) a[i] = l.get(i);
    }
    static class FastScanner {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st = new StringTokenizer("");

        String next() {
            while (!st.hasMoreTokens())
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            return st.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

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

        long[] readArrayLong(long n) {
            long[] a = new long[(int) n];
            for (int i = 0; i < n; i++) a[i] = nextLong();
            return a;
        }

        long nextLong() {
            return Long.parseLong(next());
        }
    }
}