#include <bits/stdc++.h>
using namespace std;

int main() {
	char a1[1001] = {};
	int k, a[1001] = {}, c;
	cin >> a1;
	cin >> k;
	int len = strlen(a1);
	for (int i = 0; i <= len - 1; i++) {
		a[len - 1 - i] = a1[i] - 48;
	}
	sort(a, a + len );
	for (int i = 0; i < len - k ; i++) {
		cout  << a[i];
	}
	return 0;
}