#include <bits/stdc++.h>
using namespace std;
#define F first
#define S second
#define R cin>>
#define ll long long
#define ln cout<<'\n'
#define in(a) insert(a)
#define pb(a) push_back(a)
#define pd(a) printf("%.10f\n",a)
#define mem(a) memset(a,0,sizeof(a))
#define all(c) (c).begin(),(c).end()
#define iter(c) __typeof((c).begin())
#define rrep(i,n) for(ll i=(ll)(n)-1;i>=0;i--)
#define REP(i,m,n) for(ll i=(ll)(m);i<(ll)(n);i++)
#define rep(i,n) REP(i,0,n)
#define tr(it,c) for(iter(c) it=(c).begin();it!=(c).end();it++)
ll check(ll n,ll m,ll x,ll y){return x>=0&&x<n&&y>=0&&y<m;}void pr(){ln;}
template<class A,class...B>void pr(const A &a,const B&...b){cout<<a<<(sizeof...(b)?" ":"");pr(b...);}
template<class A>void PR(A a,ll n){rep(i,n)cout<<(i?" ":"")<<a[i];ln;}
const ll MAX=1e9+7,MAXL=1LL<<61,dx[8]={-1,0,1,0,-1,-1,1,1},dy[8]={0,1,0,-1,-1,1,1,-1};
typedef pair<ll,ll> P;

vector<int> palindrome(string &s){
  int n=s.size(),k;
  vector<int> r(n*2);
  for(int i=0,j=0;i<n*2;i+=k,j=max(j-k,0)) {
    while(i-j>=0&&i+j+1<n*2&&s[(i-j)/2]==s[(i+j+1)/2])j++;r[i]=j;
    for(k=1;i-k>=0&&r[i]-k>=0&&r[i-k]!=r[i]-k;k++)r[i+k]=min(r[i-k],r[i]-k);
  }
  return r;
}

void Main() {
  ll n,m;
  cin >> n >> m;
  string s="";
  rep(i,m) s+='0';
  rep(i,m-2) {
    if(s.size()==n) break;
    s+='1';
  }
  while(s.size()<n) {
    ll x=s.back()-'0';
    x^=1;
    s+=(char)(x+'0');
  }
  rep(k,2) {
    rep(j,2) {
      vector<int> v=palindrome(s);
      ll M=0;
      rep(i,v.size()) {
        if(!v[i]) continue;
        ll l=i/2,r=i/2,z=v[i]-1;
        if(i%2) r++,z--;
        l-=z/2,r+=z/2;
        M=max(M,r-l+1);
      }
      if(M<=m) {
        pr(s);
        return;
      }
      ll x=s[n-1]-'0';
      x^=1;
      s[n-1]=(char)(x+'0');
    }
    if(n-2>=0) {
      ll x=s[n-2]-'0';
      x^=1;
      s[n-2]=(char)(x+'0');
    }
  }
  if(m>=4) {
    string t="110100";
    string s="";
    rep(i,m) s+='0';
    REP(i,m,n) s+=t[(i-m)%t.size()];
    vector<int> v=palindrome(s);
    ll M=0;
    rep(i,v.size()) {
      if(!v[i]) continue;
      ll l=i/2,r=i/2,z=v[i]-1;
      if(i%2) r++,z--;
      l-=z/2,r+=z/2;
      M=max(M,r-l+1);
    }
    if(M<=m) {
      pr(s);
      return;
    }
  }
  pr(-1);
}

int main(){ios::sync_with_stdio(0);cin.tie(0);Main();return 0;}