#include <bits/stdc++.h> using namespace std; char a[100005]; int main() { string s; cin >> s; int t; cin >> t; memset(a, -1, sizeof a); int tar = s.size() - t; long long st = 0; for (int i = tar; i >= 1; i--) { char minn = 127, minp = 0; for (int j = st; j < s.size() - i + 1; j++) { if (s[j] < minn) { minn = s[j]; minp = j; } } st = minp + 1; cout << minn; } return 0; }