func_code_string: #include <bits/stdc++.h>   using namespace std;   template <class T>   inline T gcd(T a, T b) {     if (a < 0) return gcd(-a, b);     if (b < 0) return gcd(a, -b);     return (b == 0) ? a : gcd(b, a % b);   }   const double EPS = 1e-10;   const double PI = acos(-1.0);   const int INF = 1 << 30;   const int mod = 1000000007;   const int maxm = 1 + 5;   const int maxn = 1000000 + 5;   char cat[4][100000];   char s[4][100000];   int n, k;   bool bj;   bool fit(char ch) {     if (ch ==  a  || ch ==  e  || ch ==  i  || ch ==  u  || ch ==  o )       return true;     return false;   }   void fun(int x) {     int len = strlen(s[x]);     int kk = 0, start = -1;     for (int i = len - 1; i >= 0; i--) {       if (fit(s[x][i])) kk++;       if (kk == k) {         start = i;         break;       }     }     if (kk != k)       bj = false;     else       bj = true;     for (int i = start; bj && i < len; i++) {       cat[x][i - start] = s[x][i];     }     if (bj) cat[x][len - start] =   0 ;   }   bool same(int i, int j) {     if (strcmp(cat[i], cat[j]) == 0) return true;     return false;   }   int cmp() {     if (bj == false) return -1;     if (same(0, 1) && same(1, 2) && same(2, 3)) return 0;     if (same(0, 1) && same(2, 3)) return 1;     if (same(0, 2) && same(1, 3)) return 2;     if (same(0, 3) && same(1, 2)) return 3;     return -1;   }   int main() {     int ans = -2;     scanf( %d %d , &n, &k);     for (int i = (0), _b(n); i < _b; ++i) {       for (int j = (0), _b(4); j < _b; ++j) {         scanf( %s , s[j]);         fun(j);       }       int p = cmp();       if (ans == -1)         continue;       else if (ans == -2)         ans = p;       else if (ans == 0)         ans = p;       else {         if (p == 0)           continue;         else if (ans != p)           ans = -1;       }     }     if (ans == -1)       cout <<  NO  << endl;     else if (ans == 0)       cout <<  aaaa  << endl;     else if (ans == 1)       cout <<  aabb  << endl;     else if (ans == 2)       cout <<  abab  << endl;     else if (ans == 3)       cout <<  abba  << endl;     return 0;   }   