#include <bits/stdc++.h>
using namespace std;
template <typename T>
void _dbg(const char* _s, T _h) {
  cerr << _s << " = " << _h << "\n";
}
template <typename T, typename... Ts>
void _dbg(const char* _s, T _h, Ts... _t) {
  int _b = 0;
  while (((_b += *_s == '(') -= *_s == ')') != 0 || *_s != ',') cerr << *_s++;
  cerr << " = " << _h << ",";
  _dbg(_s + 1, _t...);
}
const int64_t INF = static_cast<int64_t>(1e9) + 7;
const int64_t LINF = INF * INF;
const int MAXN = static_cast<int>(1e6) + 17;
void solve() {
  int n, l, k;
  cin >> n >> l >> k;
  vector<int> vec(26, 0);
  string second;
  cin >> second;
  for (int i = 0; i < second.size(); ++i) {
    vec[second[i] - 'a']++;
  }
  vector<string> ans(n);
  int cur_c = 0;
  int d = 0;
  int start_i = 0;
  do {
    ++d;
    for (int i = start_i; i < k; ++i) {
      while (vec[cur_c] <= 0) {
        cur_c++;
        start_i = i;
      }
      ans[i] += cur_c + 'a';
      --vec[cur_c];
    }
  } while (d < l);
  for (int i = 0; i < n; ++i) {
    for (int j = ans[i].size(); j < l; ++j) {
      while (vec[cur_c] <= 0) {
        cur_c++;
      }
      ans[i] += cur_c + 'a';
      --vec[cur_c];
    }
  }
  for (int i = 0; i < n; ++i) {
    std::cout << ans[i] << '\n';
  }
}
int main() {
  cin.tie(nullptr);
  cout.tie(nullptr);
  ios_base::sync_with_stdio(false);
  int q = 1;
  for (int i = 0; i < q; ++i) {
    solve();
  }
}
