// Problem: No.2037 NAND Pyramid
// Contest: yukicoder
// URL: https://yukicoder.me/problems/no/2037
// Memory Limit: 512 MB
// Time Limit: 2000 ms

#include <bits/stdc++.h>

#define fastio ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
#define dbg(x) cout << #x << " = " << (x) << "\n";
#define popcount(x) __builtin_popcountll((x))
#define all(v) (v).begin(), (v).end()
#define pb emplace_back
#define x first
#define y second

using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;

const int inf = 0x3f3f3f3f;
const int mod = 1e9 + 7;

int n, k;

void solve() {
  cin >> n >> k;
  vector<string> s;
  string str;
  cin >> str;
  s.push_back(str);
  for (int i = 0; i < 2; i++) {
    string str = s.back();
    string ss;
    for (int j = 1; j < str.size(); j++) {
      ss.push_back((str[j] == str[j - 1] && str[j] == '1') ? '0' : '1');
    }
    s.pb(ss);
  }
  string tmp;
  if (k % 2 == s[1].size() % 2)
    tmp = s[1];
  else
    tmp = s[2];
  int l = 0, r = tmp.size();
  cout << tmp.substr((tmp.size() - k) / 2, k) << "\n";
}

int main() {
  fastio;
  int t = 1;
  // cin >> t;
  while (t--) {
    solve();
  }
  return 0;
}