#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, a[150], k = 0, b[150], f = 0;
  char c;
  string s;
  memset(a, 0, sizeof(a));
  memset(b, 0, sizeof(b));
  cin >> n >> s;
  for (int i = 0; i < s.length(); i++) a[s[i]] = 1;
  for (int i = 0; i < 150; i++) k += a[i];
  c = s[0];
  if (k < n)
    cout << "NO";
  else {
    cout << "YES" << endl;
    for (int i = 0; i < s.length(); i++) {
      if (i == 0) {
        cout << s[i];
        b[s[i]] = 1;
      } else {
        if (c != s[i] && n - f > 1 && b[s[i]] == 0) {
          cout << endl << s[i];
          c = s[i];
          f++;
          b[s[i]] = 1;
        } else
          cout << s[i];
      }
    }
  }
}
