#include <bits/stdc++.h>
using namespace std;
int main(void) {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int n;
  cin >> n;
  vector<string> s(n);
  vector<pair<int, pair<char, int> > > a(n);
  for (__typeof(n) i = (0) - ((0) > (n)); i != (n) - ((0) > (n));
       i += 1 - 2 * ((0) > (n)))
    cin >> s[i];
  if (n < 4)
    cout << "0";
  else {
    for (__typeof(n) i = (0) - ((0) > (n)); i != (n) - ((0) > (n));
         i += 1 - 2 * ((0) > (n))) {
      int cnt = 0;
      char c;
      int len = (long long)s[i].size();
      for (__typeof(len) j = (0) - ((0) > (len)); j != (len) - ((0) > (len));
           j += 1 - 2 * ((0) > (len))) {
        if (s[i][j] == 'a' || s[i][j] == 'e' || s[i][j] == 'i' ||
            s[i][j] == 'o' || s[i][j] == 'u') {
          cnt++;
          c = s[i][j];
        }
      }
      a[i].first = cnt;
      a[i].second.second = i;
      a[i].second.first = c;
    }
    sort(a.begin(), a.end());
    int k1 = 0, k2 = 0;
    vector<string> s1;
    vector<string> s2;
    vector<string> s3;
    vector<string> s4;
    int i = 0;
    while (i < n - 1) {
      if (a[i].first == a[i + 1].first &&
          a[i].second.first == a[i + 1].second.first) {
        k1++;
        s1.emplace_back(s[a[i].second.second]);
        s3.emplace_back(s[a[i + 1].second.second]);
        a[i].second.first = 'A';
        a[i + 1].second.first = 'A';
        i = i + 2;
      } else
        i++;
    }
    sort(a.begin(), a.end());
    i = 0;
    while (i < n - 1) {
      if (a[i].first == a[i + 1].first && a[i + 1].second.first != 'A' &&
          a[i].second.first != 'A') {
        k2++;
        s2.emplace_back(s[a[i].second.second]);
        s4.emplace_back(s[a[i + 1].second.second]);
        i = i + 2;
      } else
        i++;
    }
    int ans = min((k1), (k1 + k2) / 2);
    cout << ans << '\n';
    if (k2 < ans) {
      int i = 0;
      ans = ans - k2;
      while (k2 > 0) {
        cout << s2[i] << ' ' << s1[i] << '\n';
        cout << s4[i] << ' ' << s3[i] << '\n';
        i++;
        k2--;
      }
      while (ans > 0) {
        cout << s1[i] << ' ' << s1[i + 1] << '\n';
        cout << s3[i] << ' ' << s3[i + 1] << '\n';
        ans--;
        i = i + 2;
      }
    } else {
      int i = 0;
      while (ans > 0) {
        cout << s2[i] << ' ' << s1[i] << '\n';
        cout << s4[i] << ' ' << s3[i] << '\n';
        i++;
        ans--;
      }
    }
  }
}
