#define _CRT_SECURE_NO_DEPRECATE
#include <iostream> 
#include <string>
#include <vector>
#include <sstream>
#include <queue>
#include <algorithm>
#include <iomanip>
#include <map>
#include <set>
#include <math.h>
#include <stack>
#include <deque>
#include <numeric>
#include <cstring>
#include <cstdio>
#include <cstdlib>
#include <bitset>
#define mpair make_pair
#define all(v) v.begin(),v.end()
using namespace std;
typedef long long ll;
typedef long double ld;
const ld epsylon = 1e-9;
int main()
{
  freopen("nthword.in","r",stdin);
  freopen("nthword.out", "w", stdout);

  string temp;
  cin >> temp;
  int k,n;
  cin >> k  >> n;
  int m = temp.size();
  
  vector<int> u(k, 0);

  while (n) {
    for (int i = k - 1; i >= 0; --i) {
      if (u[i] < m -1){
        u[i]++;
        for (int j = i+1; j < k;++j){
          u[j] = u[i];
        }
        break;
      }/* else {
        u[k] = -1;
      }*/
    }
    n--;
  }
  for (int i=0;i<k;++i){
    printf("%c", temp[u[i]]);
  }
  printf("\n");
  return 0;
}