#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long int t, flag = 0;
  t = 1;
  while (t--) {
    int n;
    cin >> n;
    string second[n + 1];
    map<pair<int, char>, int> mp;
    vector<pair<int, int> > v2;
    map<int, vector<int> > mp4;
    for (int i = 1; i < n + 1; i++) {
      cin >> second[i];
      int c = 0;
      char q;
      for (int j = 0; j < (int)second[i].size(); j++) {
        if (second[i][j] == 'a' || second[i][j] == 'e' || second[i][j] == 'i' ||
            second[i][j] == 'o' || second[i][j] == 'u') {
          c++;
          q = second[i][j];
        }
      }
      if (mp[make_pair(c, q)] == 0) {
        mp[make_pair(c, q)] = i;
      } else {
        v2.push_back(make_pair(i, mp[make_pair(c, q)]));
        mp[make_pair(c, q)] = 0;
      }
    }
    for (map<pair<int, char>, int>::iterator it = mp.begin(); it != mp.end();
         ++it) {
      if ((*it).second != 0) {
        mp4[((*it).first.first)].push_back((*it).second);
      }
    }
    vector<pair<int, int> > v1;
    for (map<int, vector<int> >::iterator it = mp4.begin(); it != mp4.end();
         it++) {
      vector<int> v = (*it).second;
      for (int i = 0; i < (int)v.size() - 1; i += 2) {
        v1.push_back(make_pair(v[i], v[i + 1]));
      }
    }
    int k = 0, j = 0;
    vector<int> ans;
    while (k < (int)v1.size() && j < (int)v2.size()) {
      ans.push_back(v1[k].first);
      ans.push_back(v2[j].first);
      ans.push_back(v1[k].second);
      ans.push_back(v2[j].second);
      k++;
      j++;
    }
    for (j; j < (int)v2.size() - 1; j += 2) {
      ans.push_back(v2[j].first);
      ans.push_back(v2[j + 1].first);
      ans.push_back(v2[j].second);
      ans.push_back(v2[j + 1].second);
    }
    cout << (int)ans.size() / 4 << endl;
    int i = 0;
    while (i < (int)ans.size()) {
      cout << second[ans[i]] << " " << second[ans[i + 1]] << endl
           << second[ans[i + 2]] << " " << second[ans[i + 3]] << endl;
      i += 4;
    }
  }
}
