func_code_string: #include <bits/stdc++.h>   using namespace std;   template <class T>   T gcd(T a, T b) {     if (!b) return a;     while (b ^= a ^= b ^= a %= b)       ;     return a;   }   template <class T>   T max(const T& t1, const T& t2, const T& t3) {     return max(max(t1, t2), t3);   }   template <class T>   T max(const T& t1, const T& t2, const T& t3, const T& t4) {     return max(max(t1, t2), max(t3, t4));   }   long long fpow(long long x, long long y, long long mod = 0x7fffffffffffffffll) {     long long ret = 1;     while (y) {       if (y & 1) ret *= x, ret %= mod;       x *= x;       x %= mod;       y >>= 1;     }     return ret;   }   void ex_gcd(long long a, long long b, long long& x, long long& y) {     if (b == 0) {       x = a;       y = 0;       return;     }     ex_gcd(b, a % b, y, x);     y = y - a / b * x;   }   long long modrev(long long x, long long mod) {     long long x1, x2;     ex_gcd(x, mod, x1, x2);     return x1;   }   unsigned long long T_rand() { return (unsigned long long)(rand()); }   unsigned long long Rand() {     return (T_rand() << 48) | (T_rand() << 32) | (T_rand() << 16) | T_rand();   }   template <class T>   bool PRE_INPUT_INTENGER(T& ret) {     ;     ret = 0;     char c = getchar();     if (c == -1) return 0;     bool f = 0;     while ((c <  0  || c >  9 ) && (c != -1) && (c !=  - )) c = getchar();     if (c ==  - ) {       f = 1;       c = getchar();     }     while (c >=  0  && c <=  9 ) ret *= 10, ret += c -  0 , c = getchar();     if (f) ret = -ret;     if (c == -1) return 0;     return 1;   }   bool input(int& ret) { return PRE_INPUT_INTENGER(ret); }   bool input(long long& ret) { return PRE_INPUT_INTENGER(ret); }   bool input(unsigned long long& ret) { return PRE_INPUT_INTENGER(ret); }   bool input(unsigned int& ret) { return PRE_INPUT_INTENGER(ret); }   template <class T>   bool PRE_INPUT_DOUBLE(T& ret) {     ;     ret = 0;     char c = getchar();     if (c == -1) return 0;     bool f = 0;     while ((c <  0  || c >  9 ) && (c != -1) && (c !=  . ) && (c !=  - ))       c = getchar();     bool isright = 0;     if (c ==  - ) {       f = 1;       c = getchar();     }     T t = 1;     while ((c >=  0  && c <=  9 ) || (c ==  . )) {       if (c ==  . )         isright = 1;       else {         ret *= 10, ret += c -  0 ;         if (isright) t *= 10;       }       c = getchar();     }     ret /= t;     if (f) ret = -ret;     if (c == -1) return 0;     return 1;   }   bool input(double& ret) { return PRE_INPUT_DOUBLE(ret); }   bool input(float& ret) { return PRE_INPUT_DOUBLE(ret); }   bool IS_SPECIAL_CHAR(const char& ret) {     return (ret ==     || ret ==   n  || ret ==   t  || ret ==   r  ||             ret ==   v );   }   bool input(char& ret) {     ;     ret = getchar();     if (ret == -1) return 0;     while (IS_SPECIAL_CHAR(ret)) ret = getchar();     return ~ret;   }   bool input(char* ret) {     ;     char c;     if (!input(c)) return 0;     *ret++ = c;     while (!IS_SPECIAL_CHAR(*(ret - 1))) *ret++ = getchar();     *(ret - 1) = 0;     return 1;   }   template <class T1, class T2>   bool input(T1& t1, T2& t2) {     return input(t1) && input(t2);   }   template <class T1, class T2, class T3>   bool input(T1& t1, T2& t2, T3& t3) {     return input(t1) && input(t2) && input(t3);   }   template <class T1, class T2, class T3, class T4>   bool input(T1& t1, T2& t2, T3& t3, T4& t4) {     return input(t1) && input(t2) && input(t3) && input(t4);   }   template <class T1, class T2, class T3, class T4, class T5>   bool input(T1& t1, T2& t2, T3& t3, T4& t4, T5& t5) {     return input(t1) && input(t2) && input(t3) && input(t4) && input(t5);   }   template <class T>   void input(T* a, int n) {     for (int i = 0; i <= n - 1; i++) input(a[i]);   }   template <class T>   void PRE_OUTPUT_INTENGER(const T& t) {     ;     if (!t) {       putchar( 0 );       return;     }     T key = t;     int tt[25];     if (key < 0) {       putchar( - );       key = -key;     }     int cnt = 0;     while (key) tt[cnt++] = key % 10, key /= 10;     while (cnt) putchar(tt[--cnt] +  0 );     ;   }   void output(const int& t) { PRE_OUTPUT_INTENGER(t); }   void output(const long long& t) { PRE_OUTPUT_INTENGER(t); }   void output(const unsigned long long& t) { PRE_OUTPUT_INTENGER(t); }   void output(const unsigned int& t) { PRE_OUTPUT_INTENGER(t); }   template <class T>   void PRE_OUTPUT_DOUBLE(const T& key) {     ;     printf( %.*f , 6, key);     ;   }   void output(const double& t) { PRE_OUTPUT_DOUBLE(t); }   void output(const float& t) { PRE_OUTPUT_DOUBLE(t); }   void output(const char* ch) {     ;     int cnt = 0;     while (ch[cnt]) putchar(ch[cnt++]);     ;   }   void output(const char& c) {     ;     putchar(c);     ;   }   void output(const string& s) { output(s.c_str()); }   template <class T1, class T2>   void output(const T1& t1, const T2& t2) {     output(t1);     output(t2);   }   template <class T1, class T2, class T3>   void output(const T1& t1, const T2& t2, const T3& t3) {     output(t1);     output(t2);     output(t3);   }   template <class T1, class T2, class T3, class T4>   void output(const T1& t1, const T2& t2, const T3& t3, const T4& t4) {     output(t1);     output(t2);     output(t3);     output(t4);   }   template <class T1, class T2, class T3, class T4, class T5>   void output(const T1& t1, const T2& t2, const T3& t3, const T4& t4,               const T5& t5) {     output(t1);     output(t2);     output(t3);     output(t4);     output(t5);   }   template <class T1, class T2, class T3, class T4, class T5, class T6>   void output(const T1& t1, const T2& t2, const T3& t3, const T4& t4,               const T5& t5, const T6& t6) {     output(t1);     output(t2);     output(t3);     output(t4);     output(t5);     output(t6);   }   template <class T1, class T2, class T3, class T4, class T5, class T6, class T7>   void output(const T1& t1, const T2& t2, const T3& t3, const T4& t4,               const T5& t5, const T6& t6, const T7& t7) {     output(t1);     output(t2);     output(t3);     output(t4);     output(t5);     output(t6);     output(t7);   }   template <class T>   void printal(T* a, int n) {     for (int i = 0; i < n - 1; i++) output(a[i],    );     output(a[n - 1],   n );   }   template <class T>   void printel(T* a, int n) {     for (int i = 0; i < n; i++) output(a[i],   n );   }   template <class T>   void inputal(T* a, int n) {     for (int i = 0; i <= n - 1; i++) input(a[i]);   }   const int maxn = 1e5 + 10;   struct Node {     string s;     int cnt;     char last;     bool operator<(const Node& t) const {       if (cnt < t.cnt) return true;       if (last < t.last) return true;       return false;     }     bool operator==(const Node& t) const {       return cnt == t.cnt && last == t.last;     }   };   Node node[maxn];   const char* vowel =  aeiou ;   bool is_vowel(char c) {     switch (c) {       case  a :       case  e :       case  i :       case  o :       case  u :         return true;       default:         return false;     }   }   map<int, map<char, vector<int>>> mp;   int ans[4 * maxn];   int main() {     int n;     input(n);     for (int i = 0; i <= n - 1; i++) {       cin >> node[i].s;       node[i].cnt = 0;       for (const char& c : node[i].s) {         if (is_vowel(c)) {           ++node[i].cnt;           node[i].last = c;         }       }       if (mp.count(node[i].cnt) == 0) {         mp[node[i].cnt] = map<char, vector<int>>();       }       if (mp[node[i].cnt].count(node[i].last) == 0) {         mp[node[i].cnt][node[i].last] = vector<int>();       }       mp[node[i].cnt][node[i].last].push_back(i);     }     vector<pair<int, int>> has_same;     map<int, vector<int>> single;     for (const pair<int, map<char, vector<int>>>& t : mp) {       for (const pair<char, vector<int>>& t2 : t.second) {         for (int i = 0; i < t2.second.size(); i += 2) {           if (i == t2.second.size() - 1) {             if (single.count(t.first) == 0) {               single[t.first] = vector<int>();             }             single[t.first].push_back(t2.second[i]);           } else {             has_same.push_back(make_pair(t2.second[i], t2.second[i + 1]));           }         }       }     }     int cnt = 0;     int last_double_idx = 0;     for (const pair<int, vector<int>>& t : single) {       int last_single_idx = 0;       if (last_double_idx == has_same.size()) break;       while (t.second.size() - last_single_idx > 1) {         if (last_double_idx == has_same.size()) break;         pair<int, int>& cur = has_same[last_double_idx++];         ans[cnt++] = t.second[last_single_idx++];         ans[cnt++] = cur.first;         ans[cnt++] = t.second[last_single_idx++];         ans[cnt++] = cur.second;       }     }     while (last_double_idx + 1 < has_same.size()) {       ans[cnt++] = has_same[last_double_idx].first;       ans[cnt++] = has_same[last_double_idx + 1].first;       ans[cnt++] = has_same[last_double_idx].second;       ans[cnt++] = has_same[last_double_idx + 1].second;       last_double_idx += 2;     }     output(cnt / 4);     putchar(  n );     for (int i = 0; i < cnt; i += 2) {       output(node[ans[i]].s,    , node[ans[i + 1]].s);       putchar(  n );     }   }   