#include <bits/stdc++.h>
using namespace std;
struct myhash {
  static uint64_t splitmix64(uint64_t x) {
    x += 0x9e3779b97f4a7c15;
    x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
    x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
    return x ^ (x >> 31);
  }
  size_t operator()(uint64_t x) const {
    static const uint64_t FIXED_RANDOM =
        chrono::steady_clock::now().time_since_epoch().count();
    return splitmix64(x + FIXED_RANDOM);
  }
};
long long modpow(long long base, long long exp, long long modulus) {
  base %= modulus;
  long long result = 1;
  while (exp > 0) {
    if (exp & 1) result = (result * base) % modulus;
    base = (base * base) % modulus;
    exp >>= 1;
  }
  return result;
}
long long modinv(long long a, long long m) {
  long long m0 = m;
  long long y = 0, x = 1;
  if (m == 1) return 0;
  while (a > 1) {
    long long q = a / m;
    long long t = m;
    m = a % m, a = t;
    t = y;
    y = x - q * y;
    x = t;
  }
  if (x < 0) x += m0;
  return x;
}
int main() {
  long long n;
  cin >> n;
  vector<string> s(n);
  for (long long(i) = (0); i < (n); ++(i)) cin >> s[i];
  map<long long, unordered_map<char, vector<string>>> m;
  vector<pair<string, string>> secondwords(0);
  vector<vector<string>> firstwords(0);
  unordered_map<long long, long long> fq;
  vector<long long> poss(0);
  for (long long(i) = (0); i < (n); ++(i)) {
    char lastvowel;
    long long numvowels = 0;
    for (long long(j) = (0); j < (s[i].length()); ++(j)) {
      switch (s[i][j]) {
        case 'a':
        case 'e':
        case 'i':
        case 'o':
        case 'u':
          numvowels++;
          lastvowel = s[i][j];
          break;
      }
    }
    if (!fq[numvowels]) {
      fq[numvowels] = 1;
      poss.push_back(numvowels);
    }
    m[numvowels][lastvowel].push_back(s[i]);
  }
  vector<char> st{'a', 'e', 'i', 'o', 'u'};
  for (long long(i) = (0); i < (poss.size()); ++(i)) {
    vector<string> ones(0);
    for (long long(j) = (0); j < (st.size()); ++(j)) {
      for (long long(k) = (0); k < (m[poss[i]][st[j]].size() / 2); ++(k)) {
        secondwords.push_back(
            {m[poss[i]][st[j]][k * 2], m[poss[i]][st[j]][k * 2 + 1]});
      }
      if (m[poss[i]][st[j]].size() % 2 == 1) {
        ones.push_back(m[poss[i]][st[j]][m[poss[i]][st[j]].size() - 1]);
      }
    }
    firstwords.push_back(ones);
  }
  long long np = secondwords.size();
  vector<pair<string, string>> fans(0);
  for (long long(i) = (0); i < (firstwords.size()); ++(i)) {
    for (long long(j) = (0); j < (firstwords[i].size() / 2); ++(j)) {
      fans.push_back({firstwords[i][j * 2], firstwords[i][j * 2 + 1]});
    }
  }
  if (fans.size() >= secondwords.size()) {
    cout << secondwords.size() << "\n";
    for (long long(i) = (0); i < (secondwords.size()); ++(i)) {
      cout << fans[i].first << " " << secondwords[i].first << "\n";
      cout << fans[i].second << " " << secondwords[i].second << "\n";
    }
  } else {
    long long sc = secondwords.size(), fw = fans.size();
    while (sc > fw) {
      sc--;
      fw++;
      fans.push_back(secondwords[sc]);
    }
    cout << sc << "\n";
    for (long long(i) = (0); i < (sc); ++(i)) {
      cout << fans[i].first << " " << secondwords[i].first << "\n";
      cout << fans[i].second << " " << secondwords[i].second << "\n";
    }
  }
}
