#include <bits/stdc++.h>
using namespace std;
long long n, m, k, mul, jum[1010];
string s, z[1010];
int main() {
  cin >> n >> m >> k;
  cin >> s;
  long long sl = s.length();
  sort(s.begin(), s.end());
  long long x = 0;
  long long y = 1;
  for (long long i = 0; i < sl; i++) {
    x++;
    if (x > k) x = y;
    if (i == 0 || s[i] != s[i - 1]) y = x;
    jum[x]++;
    z[x] += s[i];
    if (jum[k] == m) {
      mul = i + 1;
      break;
    }
  }
  for (long long i = 1; i <= n; i++) {
    while (jum[i] < m) {
      jum[i]++;
      z[i] += s[mul];
      mul++;
    }
  }
  for (long long i = 1; i <= n; i++) cout << z[i] << "\n";
  return 0;
}
