#include <bits/stdc++.h>
using namespace std;
void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
void __print(long long x) { cerr << x; }
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\'' << x << '\''; }
void __print(const char *x) { cerr << '\"' << x << '\"'; }
void __print(const string &x) { cerr << '\"' << x << '\"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }
template <typename T, typename V>
void __print(const pair<T, V> &x) {
  cerr << '{';
  __print(x.first);
  cerr << ',';
  __print(x.second);
  cerr << '}';
}
template <typename T>
void __print(const T &x) {
  int f = 0;
  cerr << '{';
  for (auto &i : x) cerr << (f++ ? "," : ""), __print(i);
  cerr << "}";
}
void _print() { cerr << "]\n"; }
template <typename T, typename... V>
void _print(T t, V... v) {
  __print(t);
  if (sizeof...(v)) cerr << ", ";
  _print(v...);
}
void pre() {}
void solve() {}
string t[1009];
int main() {
  cin.sync_with_stdio(0);
  cin.tie(0);
  cin.exceptions(cin.failbit);
  pre();
  int n, l, k;
  cin >> n >> l >> k;
  string s;
  cin >> s;
  sort(s.begin(), s.end());
  reverse(s.begin(), s.end());
  int st = 0;
  for (int i = 0; i < (l); ++i) {
    for (int j = st; j <= (k - 1); ++j) {
      t[j] += s.back();
      s.pop_back();
    }
    int x = st;
    for (int j = x; j <= (k - 1); ++j) {
      if (t[j].back() != t[k - 1].back()) {
        st++;
      } else
        break;
    }
  }
  reverse(s.begin(), s.end());
  st = 0;
  for (int i = 0; i < (n); ++i) {
    int x = l - (int)(t[i]).size();
    t[i] += s.substr(st, x);
    st += x;
    cout << t[i] << '\n';
  }
  return 0;
}
