description: You are given an integer n. Find any string s of length n consisting only of English lowercase letters such that each non-empty substring of s occurs in s an odd number of times. If there are multiple such strings, output any. It can be shown that such string always exists under the given constraints.
  
  A string a is a substring of a string b if a can be obtained from b by deletion of several (possibly, zero or all) characters from the beginning and several (possibly, zero or all) characters from the end.
  
  Input
  
  The first line contains a single integer t (1 ≤ t ≤ 500) — the number of test cases.
  
  The first line of each test case contains a single integer n (1 ≤ n ≤ 10^5).
  
  It is guaranteed that the sum of n over all test cases doesn't exceed 3 ⋅ 10^5.
  
  Output
  
  For each test case, print a single line containing the string s. If there are multiple such strings, output any. It can be shown that such string always exists under the given constraints.
  
  Example
  
  Input
  
  
  4
  3
  5
  9
  19
  
  
  Output
  
  
  abc
  diane
  bbcaabbba
  youarethecutestuwuu
  
  Note
  
  In the first test case, each substring of "abc" occurs exactly once.
  
  In the third test case, each substring of "bbcaabbba" occurs an odd number of times. In particular, "b" occurs 5 times, "a" and "bb" occur 3 times each, and each of the remaining substrings occurs exactly once.
solution: 
  import java.io.*;
  import java.util.*;
  
  public class Diana implements Runnable {
  
      void solve() {
          int t = ri();
          while (t-- > 0) {
              sbr = new StringBuilder();
              int n = ri();
              if (n < 27) {
                  for (int i = 0; i < n; i++) {
                      sbr.append((char) (i + 'a'));
                  }
                  println(sbr.toString());
              } else {
                  n--;
                  int half = n / 2;
                  sbr.append(get('b', half));
                  sbr.append('a');
                  sbr.append(get('b', half - 1));
                  int c = 2;
                  while (sbr.length() != n + 1) {
                      sbr.append((char)(c + 'a'));
                      c++;
                  }
  
  
  //                //Test
  //                Map<String, Integer> map = new HashMap<>();
  //                for (int i = 0; i < sbr.length(); i++) {
  //                    if (sbr.charAt(i) == 'a') continue;
  //                    StringBuilder s = new StringBuilder();
  //                    for (int j = i; j < i + 1 && j < sbr.length(); j++) {
  //                        s.append(sbr.charAt(j));
  //                    }
  //                    map.put(s.toString(), map.getOrDefault(s.toString(), 0) + 1);
  //                }
                  println(sbr.toString());
              }
  
          }
      }
  
      String get(char c, int count) {
          StringBuilder sbr = new StringBuilder();
          while (count-- > 0)
              sbr.append(c);
          return sbr.toString();
      }
  
      /************************************************************************************************************************************************/
      public static void main(String[] args) throws IOException {
          new Thread(null, new Diana(), "1").start();
      }
  
      static PrintWriter out = new PrintWriter(System.out);
      static Reader read = new Reader();
      static StringBuilder sbr = new StringBuilder();
      static int mod = (int) 1e9 + 7;
      static int dmax = Integer.MAX_VALUE;
      static long lmax = Long.MAX_VALUE;
      static int dmin = Integer.MIN_VALUE;
      static long lmin = Long.MIN_VALUE;
      static int[] dprimes = new int[]{1, 11, 101, 1087, 99991, 100001, 1000003, 15485863, 999999937};
  
      @Override
      public void run() {
          solve();
          out.close();
      }
  
      static class Reader {
          private byte[] buf = new byte[1024];
          private int index;
          private InputStream in;
          private int total;
  
          public Reader() {
              in = System.in;
          }
  
          public int scan() throws IOException {
              if (total < 0)
                  throw new InputMismatchException();
              if (index >= total) {
                  index = 0;
                  total = in.read(buf);
                  if (total <= 0)
                      return -1;
              }
              return buf[index++];
          }
  
          public int intNext() throws IOException {
              int integer = 0;
              int n = scan();
              while (isWhiteSpace(n))
                  n = scan();
              int neg = 1;
              if (n == '-') {
                  neg = -1;
                  n = scan();
              }
              while (!isWhiteSpace(n)) {
                  if (n >= '0' && n <= '9') {
                      integer *= 10;
                      integer += n - '0';
                      n = scan();
                  } else
                      throw new InputMismatchException();
              }
              return neg * integer;
          }
  
          public double doubleNext() throws IOException {
              double doub = 0;
              int n = scan();
              while (isWhiteSpace(n))
                  n = scan();
              int neg = 1;
              if (n == '-') {
                  neg = -1;
                  n = scan();
              }
              while (!isWhiteSpace(n) && n != '.') {
                  if (n >= '0' && n <= '9') {
                      doub *= 10;
                      doub += n - '0';
                      n = scan();
                  } else
                      throw new InputMismatchException();
              }
              if (n == '.') {
                  n = scan();
                  double temp = 1;
                  while (!isWhiteSpace(n)) {
                      if (n >= '0' && n <= '9') {
                          temp /= 10;
                          doub += (n - '0') * temp;
                          n = scan();
                      } else
                          throw new InputMismatchException();
                  }
              }
              return doub * neg;
          }
  
          public String read() throws IOException {
              StringBuilder sb = new StringBuilder();
              int n = scan();
              while (isWhiteSpace(n))
                  n = scan();
              while (!isWhiteSpace(n)) {
                  sb.append((char) n);
                  n = scan();
              }
              return sb.toString();
          }
  
          public String rline() throws IOException {
              StringBuilder sb = new StringBuilder();
              int n = scan();
              while (n != '\n') {
                  sb.append((char) n);
                  n = scan();
              }
              return sb.toString();
          }
  
          private boolean isWhiteSpace(int n) {
              if (n == ' ' || n == '\n' || n == '\r' || n == '\t' || n == -1)
                  return true;
              return false;
          }
      }
  
      static void print(Object object) {
          out.print(object);
      }
  
      static void println(Object object) {
          out.println(object);
      }
  
      static int[] iArr(int len) {
          return new int[len];
      }
  
      static long[] lArr(int len) {
          return new long[len];
      }
  
      static long min(long a, long b) {
          return Math.min(a, b);
      }
  
      static int min(int a, int b) {
          return Math.min(a, b);
      }
  
      static long max(Long a, Long b) {
          return Math.max(a, b);
      }
  
      static int max(int a, int b) {
          return Math.max(a, b);
      }
  
      static int ri() {
          try {
              return read.intNext();
          } catch (IOException e) {
              e.printStackTrace();
          }
          System.exit(2);
          return -1;
      }
  
      static long rl() {
          try {
              return Long.parseLong(read.read());
          } catch (IOException e) {
              e.printStackTrace();
          }
          System.exit(2);
          return -1;
      }
  
      static String rs() {
          try {
              return read.read();
          } catch (IOException e) {
              e.printStackTrace();
          }
          System.exit(2);
          return "";
      }
  
      static String rline() {
          try {
              return read.rline();
          } catch (IOException e) {
              e.printStackTrace();
          }
          System.exit(2);
          return "";
      }
  
      static char rc() {
          return rs().charAt(0);
      }
  
      static double rd() {
          try {
              return read.doubleNext();
          } catch (IOException e) {
              e.printStackTrace();
          }
          System.exit(2);
          return -1;
      }
  }
  