#include <bits/stdc++.h>
using namespace std;
long long n, m, t, a[3000001], k;
int main()
{
scanf("%d%d", &n, &m);
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) cout<<"0";
for (int i = 1; i <= n; i++)
{
if (a[i] != -1){
if (k > 0) cout<<"110";
else cout<<"10";
k--;
}
}
if (a[m + 1] != -1) {
if (k > 0) cout<<"11"<<endl;
else cout<<"1"<<endl;
}
}
else cout<<"-1"<<endl;
}
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