#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic pop
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;

} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, k;
  cin >> n >> k;
  string s;
  cin >> s;
  rep(i, n) if (s[i] == '1') {
    if ((i == 0 || s[i - 1] == '0') && 
        (i == n - 1 || s[i + 1] == '0')) {
      s[i] = '0';
    }
  }
  int r = n - k;
  int r2 = r / 2;
  string t = s.substr(r2, n - 2 * r2);
  if (r % 2) {
    int sz = t.size();
    string u(sz - 1, '.');
    rep(i, sz - 1) {
      u[i] = t[i] == '1' && t[i + 1] == '1' ? '0' : '1';
    }
    swap(t, u);
  }
  cout << t << '\n';
}