#include <bits/stdc++.h>
#define _kiet int main ()
#define ll long long
#define str string
#define fir first
#define sec second
#define ld long double
#define pb push_back
#define MOD 100000009
#define freopen(name) if(fopen(name".INP","r")) {freopen (name".INP","r",stdin); freopen (name".OUT","w",stdout);}
#define ALL(x) (x).begin(),(x).end()
using namespace std;
const int Max_n=1e6;
_kiet
{
    freopen("KTH");
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    str s; cin >> s;
    int dem=1,k; cin >> k;
    sort (ALL(s));
    int i;
    for (i=s.size()-1;dem!=k&&i>=0;i--)
    {
        if (s[i]!=s[i-1])
        {
            dem++;
        }
    }
    cout << s[i];
    return 0;
}