#include <bits/stdc++.h>
using namespace std;
long long power(long long x, long long y, long long p) {
  long long res = 1;
  x = x % p;
  while (y > 0) {
    if (y & 1) res = (res * x) % p;
    y = y >> 1;
    x = (x * x) % p;
  }
  return res;
}
bool comp(long long a, long long b) { return a > b; }
void solve() {
  long long n, i, count, j;
  cin >> n;
  string vowel = "aeiou";
  string s;
  map<long long, std::vector<string>> m[5];
  for (i = 0; i < n; i++) {
    cin >> s;
    char last;
    count = 0;
    for (auto c : s) {
      if (vowel.find(c) != string::npos) {
        count++;
        last = vowel.find(c);
      }
    }
    m[last][count].push_back(s);
  }
  std::vector<string> rem;
  std::vector<pair<string, string>> ans2, ans1;
  for (j = 0; j < 5; j++) {
    for (auto val : m[j]) {
      std::vector<string> temp = val.second;
      for (i = 0; i < (temp.size() / 2) * 2; i += 2) {
        ans2.push_back({temp[i], temp[i + 1]});
      }
      if (temp.size() % 2) rem.push_back(temp.back());
    }
  }
  map<long long, std::vector<string>> m1;
  for (i = 0; i < rem.size(); i++) {
    count = 0;
    for (auto c : rem[i])
      if (vowel.find(c) != string::npos) count++;
    m1[count].push_back(rem[i]);
  }
  for (auto val : m1) {
    std::vector<string> temp = val.second;
    for (i = 0; i < (temp.size() / 2) * 2; i += 2) {
      ans1.push_back({temp[i], temp[i + 1]});
    }
  }
  long long z = ans2.size();
  if (ans2.size() >= ans1.size()) {
    z = (ans2.size() + ans1.size()) / 2;
    for (i = z; i < ans2.size(); i++) ans1.push_back(ans2[i]);
  }
  cout << z << endl;
  for (i = 0; i < z; i++) {
    cout << ans1[i].first << " " << ans2[i].first << endl;
    cout << ans1[i].second << " " << ans2[i].second << endl;
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long t;
  t = 1;
  while (t--) solve();
}
