#include <bits/stdc++.h>
#define ll long long
#define ldb long double
#define pii pair<int,int>
#define pll pair<ll,ll>
#define pli pair<ll,int>
#define pil pair<int,ll>
#define fi first
#define se second
#define inf (INT_MAX/2-1)
#define infl (1LL<<60)
#define vi vector<int>
#define pb push_back
#define sz(a) (int)(a).size()
#define all(a) begin(a),end(a)
#define y0 y5656
#define y1 y7878
#define aaa system("pause");
#define dbg(x) cerr<<(#x)<<": "<<(x)<<'\n',aaa
#define dbga(x,n) cerr<<(#x)<<"[]: ";for(int _=0;_<n;_++)cerr<<x[_]<<' ';cerr<<'\n',aaa
#define dbgs(x) cerr<<(#x)<<"[stl]: ";for(int _:x)cerr<<_<<' ';cerr<<'\n',aaa
#define dbgp(x) cerr<<(#x)<<": "<<x.fi<<' '<<x.se<<'\n',aaa
#define maxn 100

using namespace std;

ifstream fin ("pavare2.in");
ofstream fout ("pavare2.out");

int n, a, b;
ll da[maxn+5][maxn+5], db[maxn+5][maxn+5], suma[maxn+5][maxn+5], sumb[maxn+5][maxn+5];

void upd (int i) {
  suma[i][0] = da[i][0];
  for (int j = 1; j <= a; j++) suma[i][j] = suma[i][j-1] + da[i][j];
  sumb[i][0] = db[i][0];
  for (int j = 1; j <= b; j++) sumb[i][j] = sumb[i][j-1] + db[i][j];
}

vi ans;

void parcurg (int i, int x, int y, ll k) {
  if (i > n) return;
  if (x == a) {
    ans.pb(1);
    parcurg(i+1, 0, y+1, k);
    return;
  }
  ll cnt = suma[n-i][min(n-i,a-x-1)] + sumb[n-i][min(n-i,b)];
  if (i == n) cnt = 1;
  if (cnt >= k) {
    ans.pb(0);
    parcurg(i+1, x+1, 0, k);
    return;
  }
  ans.pb(1);
  parcurg(i+1, 0, y+1, k-cnt);
}

int main () {
  ll k; fin >> n >> a >> b >> k;
  int i, j, z;
  da[0][0] = db[0][0] = 1;
  for (i = 1; i <= n; i++) {
    upd(i-1);
    da[i][1] = sumb[i-1][min(b,i-1)];
    for (j = 2; j <= min(a,i); j++) da[i][j] = da[i-1][j-1];
    db[i][1] = suma[i-1][min(a,i-1)];
    for (j = 2; j <= min(b,i); j++) db[i][j] = db[i-1][j-1];
  }
  upd(n);
  fout << suma[n][a] + sumb[n][b] << '\n';
  parcurg(1, 0, 0, k);
  for (int x: ans) fout << x;
  fin.close(); fout.close();
  return 0;
}