#include <bits/stdc++.h>
const long long N = 1000005;
const long long mod = 1e9 + 7;
using namespace std;
char a[] = {'a', 'e', 'i', 'o', 'u'};
std::map<pair<long long, long long>, std::vector<long long>> v;
std::map<char, long long> mp;
void solve() {
  long long n, m, x = 0, y = 0, c = 0, q, ans = 0;
  cin >> n;
  string s[n];
  mp['a'] = 0;
  mp['e'] = 1;
  mp['i'] = 2;
  mp['o'] = 3;
  mp['u'] = 4;
  char ch = 'a';
  char st[n];
  for (long long i = 0; i < n; ++i) {
    cin >> s[i];
    c = 0;
    for (long long j = 0; j < s[i].size(); j++) {
      for (long long k = 0; k < 5; k++) {
        if (s[i][j] == a[k]) {
          c++;
          ch = s[i][j];
        }
      }
    }
    v[{c, mp[ch]}].push_back(i);
  }
  std::vector<pair<pair<long long, long long>, pair<long long, long long>>> vec;
  std::vector<pair<long long, long long>> v1, v2;
  for (auto it : v) {
    if (it.first.first == 0) continue;
    std::vector<long long> vect;
    for (long long j = 0; j < 5; j++) {
      x = v[{it.first.first, j}].size();
      while (x > 1) {
        v[{it.first.first, j}].back();
        long long t1 = v[{it.first.first, j}].back();
        v[{it.first.first, j}].pop_back();
        long long t2 = v[{it.first.first, j}].back();
        v[{it.first.first, j}].pop_back();
        x -= 2;
        v1.push_back({t1, t2});
      }
      x = v[{it.first.first, j}].size();
      if (x % 2 != 0) {
        vect.push_back(v[{it.first.first, j}].back());
        v[{it.first.first, j}].pop_back();
      }
    }
    for (int z = 0; z < (vect.size() / 2) * 2; z += 2) {
      v2.push_back({vect[z], vect[z + 1]});
    }
  }
  x = min(v1.size(), v2.size());
  for (int i = 0; i < x; ++i) {
    vec.push_back({{v2[i].first, v2[i].second}, {v1[i].first, v1[i].second}});
  }
  for (int i = (v1.size() - 1); i > x; i -= 2) {
    vec.push_back(
        {{v1[i].first, v1[i].second}, {v1[i - 1].first, v1[i - 1].second}});
  }
  cout << vec.size() << "\n";
  for (int i = 0; i < vec.size(); ++i) {
    cout << s[vec[i].first.first] << " " << s[vec[i].second.first] << "\n"
         << s[vec[i].first.second] << " " << s[vec[i].second.second] << "\n";
  }
}
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long T = 1;
  while (T--) {
    solve();
  }
  return 0;
}
