#include<bits/stdc++.h>

using namespace std;

vector<char>ch;

bool taken[150];

string s;
int k;

void backtracking(int len,int start)
{
    int i,j,a;
    char c;

    if(ch.size()==k)
    {
        for(i=0; i<k; i++)
        {
            cout<<ch[i];
        }

        puts("");

        return;
    }

    for(j=start; j<len; )
    {
        c = s[j];

        ch.push_back(c);

        backtracking(len,j+1);

        ch.pop_back();

        while(s[j]==c)j++;
    }
    return;
}

int main()
{
    int len,i;

    while(cin>>s)
    {
        scanf("%d",&k);

        sort(s.begin(),s.end());

        len = s.length();

        backtracking(len,0);

    }

    return 0;
}