#include <bits/stdc++.h>
#pragma GCC target("sse2")
#pragma GCC optimization("O2")
#pragma GCC optimization("unroll-loops")
#pragma GCC optimize "trapv"
using namespace std;
const int maxn = 1000500;
inline int g() {
  int x;
  cin >> x;
  return x;
}
inline long long gl() {
  long long x;
  cin >> x;
  return x;
}
inline char gc() {
  char x;
  cin >> x;
  return x;
}
inline string gs() {
  string s;
  cin >> s;
  return s;
}
template <typename T>
inline vector<T> gv(int len) {
  vector<T> a(len);
  for (auto &it : a) cin >> it;
  return a;
}
inline vector<int> gv(int len) {
  vector<int> a(len);
  for (auto &it : a) cin >> it;
  return a;
}
inline vector<pair<int, int>> gv_andPairCnt(int len) {
  vector<pair<int, int>> a(len);
  int i = 1;
  for (auto &it : a) {
    it.second = i;
    i++;
    cin >> it.first;
  }
  return a;
}
double power_log(double power, double val) { return log(val) / log(power); }
template <typename T>
T sqr(T x) {
  return x * x;
}
template <typename T>
ostream &operator<<(ostream &os, const vector<T> &v) {
  for (auto it : v) os << it << ", ";
  os << "\n";
  return os;
}
template <typename T>
ostream &operator<<(ostream &os, const deque<T> &v) {
  os << "deque:{";
  for (auto it : v) os << it << " ";
  os << "}\n";
  return os;
}
template <typename T>
ostream &operator<<(ostream &os, const set<T> &v) {
  os << "set:{";
  for (auto it : v) os << it << " ";
  os << "}";
  return os;
}
template <typename T, typename T2>
ostream &operator<<(ostream &os, const map<T, T2> &v) {
  os << "map:{\n";
  for (auto it : v) os << "    {" << it.first << " <> " << it.second << "}\n";
  os << "}\n";
  return os;
}
template <typename T, typename T2>
ostream &operator<<(ostream &os, const pair<T, T2> &v) {
  os << "{" << v.first << ", " << v.second << "}";
  return os;
}
template <typename T, typename H>
inline vector<pair<T, H>> gv_andBiPair(int len) {
  vector<pair<T, H>> a(len);
  for (auto &it : a) {
    cin >> it.first >> it.second;
  }
  return a;
}
template <typename T>
inline set<T> vector_to_set(const vector<T> &vec) {
  set<T> s;
  for (auto &it : vec) s.insert(it);
  return s;
}
const long long md = 1e9 + 7;
vector<int> arr[maxn];
int cnt[maxn], cnt2[maxn];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  int n = g();
  map<char, int> mp;
  string s;
  cin >> s;
  for (auto &it : s) {
    mp[it]++;
  }
  auto solve = [&](int len) {
    map<char, int> mp2 = mp;
    vector<char> odd;
    if ((n / len) % 2 != 0) {
      for (auto &it : mp2) {
        if (it.second % 2 != 0) {
          odd.push_back(it.first);
          it.second--;
        }
      }
      if (odd.size() != len) {
        for (auto &it : mp2) {
          while (it.second > 1 && odd.size() < len) {
            odd.push_back(it.first);
            odd.push_back(it.first);
            it.second -= 2;
          }
        }
      }
      if (odd.size() != len) {
        return;
      }
    }
    vector<string> ans;
    for (int T = 0; T < (len); ++T) {
      string tmp;
      for (auto &it : mp2) {
        while (it.second > 1 && tmp.size() != (n / len) / 2) {
          it.second -= 2;
          tmp += it.first;
        }
      }
      if (tmp.size() != (n / len) / 2) {
        return;
      }
      string tmp2 = tmp;
      if ((n / len) % 2 != 0) {
        assert(!odd.empty());
        tmp2 += odd.back();
        odd.pop_back();
      }
      reverse(tmp.begin(), tmp.end());
      tmp2 += tmp;
      ans.push_back(tmp2);
    }
    cout << len << "\n";
    for (auto &it : ans) {
      cout << it << " ";
    }
    exit(0);
  };
  vector<int> arr;
  for (long long i = 1; i * i <= s.size(); i++) {
    if (n % i == 0) {
      arr.push_back(i);
      if (i != n / i) {
        arr.push_back(n / i);
      }
    }
  }
  sort(arr.begin(), arr.end());
  for (auto &it : arr) {
    solve(it);
  }
}
