#include <iostream>
#include <fstream>
#include <stack>
using namespace std;
ifstream fin("alibaba.in");
ofstream fout("alibaba.out");
stack<int> stiva;

void afis(stack<int> stiva)
{if(!stiva.empty())
   {int x = stiva.top();
    stiva.pop();
    afis(stiva);
    fout<<x;}


}
int main()
{
    int N,K,i,x,ok=0;
    char nr[10000];
    ///ok-nr cifre taiate
    fin>>N>>K;
    fin>>nr;

    for(i=0;i<N && ok<K;i++)
    {x = nr[i] - '0';
        while(!stiva.empty() && ok <K && x > stiva.top()){
            stiva.pop();
            ok++;
        }
    if(stiva.size() < N-K)
            stiva.push(x);
    else
            ok++;
    }

    afis(stiva);

    return 0;
}