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 CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
const long long int MOD = 0ll;
const long long int INF = 3e18;
long long int power(long long int base, long long int exp) {
  long long int res = 1;
  while (exp > 0) {
    if (exp % 2 == 1) res = (res * base);
    base = (base * base);
    exp /= 2;
  }
  return res;
}
long long int bitc(long long int n, long long int x) { return ((n >> x) & 1); }
long long int __gcd(long long int a, long long int b) {
  return b == 0 ? a : __gcd(b, a % b);
}
long long int fsub(long long int a, long long int b, long long int p = MOD) {
  return ((a % p) - (b % p) + p) % p;
}
long long int fmult(long long int a, long long int b, long long int p = MOD) {
  return ((((a % p) * (b % p)) % p) + p) % p;
}
long long int fadd(long long int a, long long int b, long long int p = MOD) {
  return ((a % p + b % p) % p + p) % p;
}
long long int fpow(long long int n, long long int k, long long int p = MOD) {
  long long int r = 1;
  while (k > 0) {
    if (k & 1) r = r * n % p;
    n = n * n % p;
    k = k >> 1;
  }
  return r;
}
long long int inv(long long int a, long long int p = MOD) {
  return fpow(a, p - 2, p);
}
long long int fdiv(long long int a, long long int b, long long int p = MOD) {
  long long int yinv = inv(b);
  long long int ans = (a * yinv) % p;
  return ((ans) % p + p) % p;
}
long long int ceil(long long int a, long long int b) {
  return ceil((long double)a / b);
}
template <typename T>
istream &operator>>(istream &in, vector<T> &a) {
  for (auto &item : a) {
    in >> item;
  }
  return in;
}
template <typename T, typename U>
ostream &operator<<(ostream &out, pair<T, U> &a) {
  cout << a.first << " " << a.second;
  return out;
}
template <typename T, typename U>
istream &operator>>(istream &out, pair<T, U> &a) {
  cin >> a.first >> a.second;
  return out;
}
template <typename T, typename U>
ostream &operator<<(ostream &out, map<T, U> &a) {
  for (auto &item : a) {
    out << item << "\n";
  }
  return out;
}
template <typename T>
ostream &operator<<(ostream &out, vector<T> &a) {
  for (auto &item : a) {
    out << item << " ";
  }
  return out;
}
template <typename T>
ostream &operator<<(ostream &out, vector<vector<T>> &a) {
  for (auto &item : a) {
    out << item << "\n";
  }
  return out;
}
template <int D, typename T>
struct Vec : public vector<Vec<D - 1, T>> {
  static_assert(D >= 1, "Vector dimension must be greater than zero!");
  template <typename... Args>
  Vec(int n = 0, Args... args)
      : vector<Vec<D - 1, T>>(n, Vec<D - 1, T>(args...)) {}
};
template <typename T>
struct Vec<1, T> : public vector<T> {
  Vec(int n = 0, T val = T()) : vector<T>(n, val) {}
};
std::vector<bool> is_prime;
std::vector<long long int> primes;
void sieve(long long int n) {
  is_prime.resize(n + 2, true);
  primes.clear();
  long long int p;
  for (p = 2; p * p <= n; p++) {
    if (is_prime[p]) {
      long long int i;
      for (i = p * p; i <= n; i += p) {
        is_prime[i] = false;
      }
    }
  }
  is_prime[0] = is_prime[1] = false;
  long long int i;
  for (i = 2; i <= n; i++) {
    if (is_prime[i]) {
      primes.emplace_back(i);
    }
  }
}
map<long long int, long long int> prime_factors(long long int n) {
  map<long long int, long long int> s;
  long long int i;
  long long int tc = 0;
  while (n % 2 == 0) {
    tc++;
    n /= 2;
  }
  if (tc > 0) {
    s[2] = tc;
  }
  for (i = 3; i <= sqrt(n); i += 2) {
    tc = 0;
    while (n % i == 0) {
      tc++;
      n /= i;
    }
    if (tc > 0) {
      s[i] = tc;
    }
  }
  if (n > 2) {
    s[n] += 1;
  }
  return s;
}
std::vector<long long int> fact_vec;
void fact_fun(long long int n) {
  fact_vec.resize(n + 10);
  long long int i;
  fact_vec[0] = 1;
  for (i = 1; i <= n + 2; i++) {
    fact_vec[i] = (fact_vec[i - 1] * i) % MOD;
  }
}
std::vector<long long int> p2;
void power_2(long long int n, long long int m = MOD) {
  long long int i;
  p2.emplace_back(1);
  for (i = 0; i < n; i++) {
    p2.emplace_back(fmult(p2.back(), 2));
  }
}
long long int ncr(long long int n, long long int r) {
  if (r > n) return 0;
  return fdiv(fact_vec[n], fmult(fact_vec[r], fact_vec[n - r]));
}
std::vector<long long int> spf;
void sieve2(long long int MAXN) {
  MAXN += 10;
  spf.resize(MAXN, 0);
  spf[1] = 1;
  for (long long int i = 2; i < MAXN; i++) spf[i] = i;
  for (long long int i = 4; i < MAXN; i += 2) spf[i] = 2;
  for (long long int i = 3; i * i < MAXN; i++) {
    if (spf[i] == i) {
      for (long long int j = i * i; j < MAXN; j += i) {
        if (spf[j] == j) spf[j] = i;
      }
    }
  }
}
const int mi[4] = {-1, 0, 1, 0}, mj[4] = {0, 1, 0, -1};
const int d8i[8] = {-1, -1, 0, 1, 1, 1, 0, -1},
          d8j[8] = {0, 1, 1, 1, 0, -1, -1, -1};
map<long long int, long long int> getFactorization(long long int x) {
  map<long long int, long long int> ret;
  while (x != 1) {
    ret[spf[x]]++;
    x = x / spf[x];
  }
  return ret;
}
class Sol {
 public:
  Sol() { long long int i, j; }
};
int main() {
  long long int i, j;
  ios::sync_with_stdio(false);
  cin.tie(0);
  long long int ti;
  ti = 1;
  while (ti--) {
    long long int n, m;
    cin >> n >> m;
    string s;
    if (n > m + 1) {
      cout << -1 << "\n";
      return 0;
    }
    if (n == m + 1) {
      for (i = 0; i < n + m; i++) {
        if (i & 1) {
          s += '1';
        } else {
          s += '0';
        }
      }
      cout << s << "\n";
      continue;
    }
    while (n > 0 && m > 1 && n != m) {
      n--;
      m -= 2;
      s += "110";
    }
    while (n == m && n) {
      s += "10";
      n--;
      m--;
    }
    if (n) {
      s = "0" + s;
      n--;
    }
    if (m >= 1) {
      s += "1";
      m--;
    }
    if (m >= 1) {
      s += "1";
      m--;
    }
    if (n || m) {
      cout << -1 << "\n";
    } else {
      cout << s << "\n";
    }
  }
  return 0;
}