#include <bits/stdc++.h>
using namespace std;
long long dp[1000010][7];
long long kg[1000010];
long long mkg[1000010];
vector<string> vec[1000010][7];
string ans1[100010], ans2[100010], ans3[100010], ans4[100010];
int main() {
  for (int i = 1; i <= 1000000; ++i)
    for (int j = 1; j <= 5; ++j) dp[i][j] = 0;
  for (int i = 1; i <= 1000000; ++i) {
    kg[i] = 0;
  }
  long long n;
  cin >> n;
  string s[n + 10];
  char lg;
  long long tkg;
  for (int i = 1; i <= n; ++i) {
    lg = 'b';
    tkg = 0;
    cin >> s[i];
    for (int j = 0; j < s[i].size(); ++j)
      if (s[i][j] == 'a' || s[i][j] == 'i' || s[i][j] == 'o' ||
          s[i][j] == 'e' || s[i][j] == 'u') {
        lg = s[i][j];
        tkg++;
      }
    kg[tkg]++;
    if (lg == 'a') {
      dp[tkg][1]++;
      vec[tkg][1].push_back(s[i]);
    }
    if (lg == 'i') {
      dp[tkg][2]++;
      vec[tkg][2].push_back(s[i]);
    }
    if (lg == 'o') {
      dp[tkg][3]++;
      vec[tkg][3].push_back(s[i]);
    }
    if (lg == 'e') {
      dp[tkg][4]++;
      vec[tkg][4].push_back(s[i]);
    }
    if (lg == 'u') {
      dp[tkg][5]++;
      vec[tkg][5].push_back(s[i]);
    }
  }
  long long mn = 1, nmn = 1;
  long long ans = 0;
  long long h;
  for (int i = 1; i <= 1000000; ++i)
    mkg[i] = dp[i][1] + dp[i][2] + dp[i][3] + dp[i][4] + dp[i][5] -
             (dp[i][1] % 2 + dp[i][2] % 2 + dp[i][3] % 2 + dp[i][4] % 2 +
              dp[i][5] % 2);
  for (int i = 1; i <= 1000000; ++i)
    for (int j = 1; j <= 5; ++j) {
      while (dp[i][j] >= 2) {
        ans2[ans + 1] = vec[i][j][dp[i][j] - 1];
        ans4[ans + 1] = vec[i][j][dp[i][j] - 2];
        dp[i][j] -= 2;
        kg[i] -= 2;
        mkg[i] -= 2;
        while (mn <= n) {
          if (kg[mn] - 1 > mkg[mn]) {
            ans++;
            h = 1;
            while (h == 1) {
              if (dp[mn][1] % 2) {
                ans1[ans] = vec[mn][1][dp[mn][1] - 1];
                kg[mn]--;
                dp[mn][1]--;
                break;
              }
              if (dp[mn][2] % 2) {
                ans1[ans] = vec[mn][2][dp[mn][2] - 1];
                kg[mn]--;
                dp[mn][2]--;
                break;
              }
              if (dp[mn][3] % 2) {
                ans1[ans] = vec[mn][3][dp[mn][3] - 1];
                kg[mn]--;
                dp[mn][3]--;
                break;
              }
              if (dp[mn][4] % 2) {
                ans1[ans] = vec[mn][4][dp[mn][4] - 1];
                kg[mn]--;
                dp[mn][4]--;
                break;
              }
              if (dp[mn][5] % 2) {
                ans1[ans] = vec[mn][5][dp[mn][5] - 1];
                kg[mn]--;
                dp[mn][5]--;
                break;
              }
            }
            while (h == 1) {
              if (dp[mn][1] % 2) {
                ans3[ans] = vec[mn][1][dp[mn][1] - 1];
                kg[mn]--;
                dp[mn][1]--;
                break;
              }
              if (dp[mn][2] % 2) {
                ans3[ans] = vec[mn][2][dp[mn][2] - 1];
                kg[mn]--;
                dp[mn][2]--;
                break;
              }
              if (dp[mn][3] % 2) {
                ans3[ans] = vec[mn][3][dp[mn][3] - 1];
                kg[mn]--;
                dp[mn][3]--;
                break;
              }
              if (dp[mn][4] % 2) {
                ans3[ans] = vec[mn][4][dp[mn][4] - 1];
                kg[mn]--;
                dp[mn][4]--;
                break;
              }
              if (dp[mn][5] % 2) {
                ans3[ans] = vec[mn][5][dp[mn][5] - 1];
                kg[mn]--;
                dp[mn][5]--;
                break;
              }
            }
            break;
          }
          mn++;
        }
        if (mn > n) {
          while (nmn <= n) {
            if (kg[nmn] > 1) {
              ans++;
              h = 1;
              while (h == 1) {
                if (dp[nmn][1] > 0) {
                  ans1[ans] = vec[nmn][1][dp[nmn][1] - 1];
                  kg[nmn]--;
                  dp[nmn][1]--;
                  break;
                }
                if (dp[nmn][2] > 0) {
                  ans1[ans] = vec[nmn][2][dp[nmn][2] - 1];
                  kg[nmn]--;
                  dp[nmn][2]--;
                  break;
                }
                if (dp[nmn][3] > 0) {
                  ans1[ans] = vec[nmn][3][dp[nmn][3] - 1];
                  kg[nmn]--;
                  dp[nmn][3]--;
                  break;
                }
                if (dp[nmn][4] > 0) {
                  ans1[ans] = vec[nmn][4][dp[nmn][4] - 1];
                  kg[nmn]--;
                  dp[nmn][4]--;
                  break;
                }
                if (dp[nmn][5] > 0) {
                  ans1[ans] = vec[nmn][5][dp[nmn][5] - 1];
                  kg[nmn]--;
                  dp[nmn][5]--;
                  break;
                }
              }
              while (h == 1) {
                if (dp[nmn][1] > 0) {
                  ans3[ans] = vec[nmn][1][dp[nmn][1] - 1];
                  kg[nmn]--;
                  dp[nmn][1]--;
                  break;
                }
                if (dp[nmn][2] > 0) {
                  ans3[ans] = vec[nmn][2][dp[nmn][2] - 1];
                  kg[nmn]--;
                  dp[nmn][2]--;
                  break;
                }
                if (dp[nmn][3] > 0) {
                  ans3[ans] = vec[nmn][3][dp[nmn][3] - 1];
                  kg[nmn]--;
                  dp[nmn][3]--;
                  break;
                }
                if (dp[nmn][4] > 0) {
                  ans3[ans] = vec[nmn][4][dp[nmn][4] - 1];
                  kg[nmn]--;
                  dp[nmn][4]--;
                  break;
                }
                if (dp[nmn][5] > 0) {
                  ans3[ans] = vec[nmn][5][dp[nmn][5] - 1];
                  kg[nmn]--;
                  dp[nmn][5]--;
                  break;
                }
              }
              break;
            }
            nmn++;
          }
        }
      }
    }
  cout << ans << endl;
  for (int i = 1; i <= ans; ++i) {
    cout << ans1[i] << " " << ans2[i] << endl
         << ans3[i] << " " << ans4[i] << endl;
  }
  return 0;
}
