text: #include <bits/stdc++.h>
  using namespace std;
  
  #define sf scanf
  #define pf printf
  #define endl "\n"
  #define off ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)
  #define fr freopen("in.txt", "r", stdin)
  #define fw freopen("out.txt", "w", stdout)
  #define pb push_back
  #define eb emplace_back
  #define watch(x) cout<<(#x)<<" is "<<(x)<<endl
  #define pass(x) cout<<"Passed step "<<(x)<<endl
  #define RESET(a, b) memset(a, b, sizeof a)
  
  typedef long long ll;
  typedef unsigned int ui;
  typedef pair<int, int> pii;
  int mod = 1000000007; //10^9+7
  const double eps = 1e-9;
  //const double pi = 2*acos(0.0);
  //int fx[]={+1,-1,+0,+0};
  //int fy[]={+0,+0,+1,-1};
  //int fx[]={+0,+0,+1,-1,-1,+1,-1,+1};
  //int fy[]={-1,+1,+0,+0,+1,+1,-1,-1};
  
  int main()
  {
      //fr; 
      string s;
      //int size = (int)s.size();
      int n, k, i;
      cin>>n>>k;
      cin>>s;
      if(k==0) cout<<s<<endl;
      else if(n==1) cout<<'0'<<endl;
      else {
          i = 1;
          if(s[0] != '1') {
              s[0] = '1'; 
              k--; 
              i = 1;
          }
          //cout<<s<<endl;
          while(k>0 && i < n) {
              if(s[i] != '0') {
                  s[i] = '0'; 
                  k--;
              }
              i++;
          }
          cout<<s<<endl;
      }
      
      return 0;
  }
  