#include <bits/stdc++.h>
using namespace std;
#define repl(i, l, r) for (ll i = (l); i < (r); i++)
#define rep(i, n) repl(i, 0, n)
#define CST(x) cout << fixed << setprecision(x)
using ll = long long;
constexpr ll MOD = 1000000007;
constexpr int inf = 1e9 + 10;
constexpr ll INF = (ll)4e18 + 10;
constexpr int dx[9] = {1, 0, -1, 0, 1, -1, -1, 1, 0};
constexpr int dy[9] = {0, 1, 0, -1, 1, 1, -1, -1, 0};
template <typename T>
inline bool chmax(T &a, T b) {
    return ((a < b) ? (a = b, true) : (false));
}
template <typename T>
inline bool chmin(T &a, T b) {
    return ((a > b) ? (a = b, true) : (false));
}
int main() {
    cin.tie(0);
    cout.tie(0);
    ios::sync_with_stdio(false);

    int n, k;
    cin >> n >> k;
    if (k >= 4) {
        string s = "0";
        rep(i, k - 2) s += "1";
        rep(i, k - 2) s += "0";
        s += "1";
        rep(i, n) cout << s[i % (k * 2 - 2)];
        cout << endl;
    } else if (n <= k * 2) {
        rep(i, k) cout << 1;
        rep(i, n - k) cout << 0;
        cout << endl;
    } else {
        if (k == 3) {
            if (n == 7)
                cout << 1101000 << endl;
            else if (n == 8)
                cout << 11101000 << endl;
            else
                cout << -1 << endl;
        } else {
            cout << -1 << endl;
        }
    }

    return 0;
}