/*#include <iostream>
#include <cmath>
#include <vector>
#include <algorithm>
#include <array>
#include <vector>
#include <deque>
#include <set>
#include <map>
#include <string>
#include <stack>
#include <queue>
#include <unordered_map>
#include <unordered_set>
*/

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

#define int long long
#define pb push_back
#define mp make_pair
#define F first
#define S second
#define FOR(i,a,b) for(int (i)=(a);(i)<(b);(i)++)
#define REP(i,n) FOR(i,0,n)
#define ALL(a) (a).begin(),(a).end()
#define RALL(a) (a).rbegin(),(a).rend()
#define SORT(c) sort((c).begin(),(c).end())

typedef long long ll;
const ll INF = LLONG_MAX - 100;
const ll mod = 1e9 + 7;
const int MAX_N = 5e5 + 5;
int dx[] = { -1LL,0,1LL,0 }, dy[] = { 0,1LL,0,-1LL };
vector<ll> prime;

ll inv[MAX_N], fac[MAX_N];

inline ll GCD(ll a, ll b) { ll c; while (b != 0) { c = a % b; a = b; b = c; }return a; }
inline ll LCM(ll a, ll b) { return a * b / GCD(a, b); }
inline ll POW(ll a, ll b) { ll c = 1LL; while (b > 0) { if (b & 1LL) { c = a * c%mod; }a = a * a%mod; b >>= 1LL; }return c; }
inline void _nCr() { fac[0] = 1LL; for (int i = 1LL; i < MAX_N; i++) { fac[i] = fac[i - 1LL] * i%mod; }for (int i = 0; i < MAX_N; i++) { inv[i] = POW(fac[i], mod - 2); } }
inline ll nCr(ll n, ll r) { return (fac[n] * inv[r] % mod)*inv[n - r] % mod; }
inline void PRI(ll n) { bool a[n + 1LL]; for (int i = 0; i < n + 1LL; i++) { a[i] = 1LL; }for (int i = 2; i < n + 1LL; i++) { if (a[i]) { prime.pb(i); ll b = i; while (b <= n) { a[b] = 0; b += i; } } } }

class segtree {
public:
	int p = 2;
	vector<pair<char,int>> B;
	segtree(vector<pair<char,int>> &A) {
		while (A.size() > p) p *= 2;
		B = vector<pair<char,int>>(2*p-1,{'~',0});
		for (int i = 0;i < A.size();i++) {
			B[p-1+i] = A[i];
		}
		for (int i = p - 2;i >= 0;i--) {
			B[i].first = min(B[i*2+1].first,B[i*2+2].first);
			B[i].second = B[i*2+1].second + B[i*2+2].second;
		}
	}

	void update(int pos) {
		pos += p-1;
		B[pos] = {'~',0};
		pos = (pos-1)/2;
		while (pos >= 0) {
			B[pos].first = min(B[pos*2+1].first,B[pos*2+2].first);
			B[pos].second = B[pos*2+1].second + B[pos*2+2].second;
			if (pos == 0) break;
			pos = (pos-1)/2;
		}
	}

	pair<char,int> getval(int start,int end,int k = 0,int l = 0,int r = -1) {
		if (r < 0) r = p - 1;
		if (start <= l && r <= end) {return B[k];}
		if (r < start || end < l) {return {'~',0};}
		pair<char,int> L,R;
		L = getval(start,end,k*2+1,l,(l+r)/2);
		R = getval(start,end,k*2+2,(l+r)/2+1,r);
		return {min(L.first,R.first),L.second + R.second};
	}
};

signed main() {
	string s;
	int k;
	cin >> s >> k;

	vector<pair<char,int>> A;
	priority_queue<int,vector<int>,greater<int>> ch[26];
	REP (i,s.size()) {
		ch[s[i]-'a'].push(i);
		A.push_back({s[i],1});
	}

	segtree seg(A);
	string ans;
	while (k > 0) {
		int x = seg.p;
		int now = 0;
		while (x > 1) {
			if (seg.getval(0,now+x/2).second < k+2) now += x/2;
			x /= 2;
		}
		char X = seg.getval(0,now).first;
		if (X > 'z') break;
		k -= seg.getval(0,ch[X-'a'].top()).second-1;
		ans += X;
		seg.update(ch[X-'a'].top());
		ch[X-'a'].pop();
	}
	REP (i,A.size()) {
		if (seg.B[seg.p-1+i].second != 0) ans += seg.B[seg.p-1+i].first;
	}
	cout << ans << endl;
}



Measured memory_bytes: 16476