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.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.util.Arrays;
  import java.util.Random;
  import java.util.StringTokenizer;
  
  @SuppressWarnings("StringRepeatCanBeUsed")
  public final class D {
  
      public static void main(String[] args) {
          final FastScanner fs = new FastScanner();
          final StringBuilder sb = new StringBuilder();
          final int t = fs.nextInt();
          for (int test = 0; test < t; test++) {
              final int n = fs.nextInt();
              final int l = n / 2;
              final int r = l - 1;
              final int z = n % 2;
              final StringBuilder curr = new StringBuilder();
              for (int i = 0; i < l; i++) {
                  curr.append('a');
              }
              if (n != 1) {
                  curr.append('x');
              }
              for (int i = 0; i < r; i++) {
                  curr.append('a');
              }
              for (int i = 0; i < z; i++) {
                  curr.append('z');
              }
              sb.append(curr).append('\n');
          }
          System.out.println(sb);
      }
  
      static final class Utils {
          private static class Shuffler {
              private static void shuffle(int[] x) {
                  final Random r = new Random();
  
                  for (int i = 0; i <= x.length - 2; i++) {
                      final int j = i + r.nextInt(x.length - i);
                      swap(x, i, j);
                  }
              }
  
              private static void shuffle(long[] x) {
                  final Random r = new Random();
  
                  for (int i = 0; i <= x.length - 2; i++) {
                      final int j = i + r.nextInt(x.length - i);
                      swap(x, i, j);
                  }
              }
  
              private static void swap(int[] x, int i, int j) {
                  final int t = x[i];
                  x[i] = x[j];
                  x[j] = t;
              }
  
              private static void swap(long[] x, int i, int j) {
                  final long t = x[i];
                  x[i] = x[j];
                  x[j] = t;
              }
          }
  
          public static void shuffleSort(int[] arr) {
              Shuffler.shuffle(arr);
              Arrays.sort(arr);
          }
  
          public static void shuffleSort(long[] arr) {
              Shuffler.shuffle(arr);
              Arrays.sort(arr);
          }
  
          private Utils() {}
      }
  
      static class FastScanner {
          BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
          StringTokenizer st = new StringTokenizer("");
  
          private String next() {
              while (!st.hasMoreTokens()) {
                  try {
                      st = new StringTokenizer(br.readLine());
                  } catch (IOException e) {
                      //noinspection CallToPrintStackTrace
                      e.printStackTrace();
                  }
              }
              return st.nextToken();
          }
  
          int nextInt() {
              return Integer.parseInt(next());
          }
  
          long nextLong() {
              return Long.parseLong(next());
          }
  
          int[] nextIntArray(int n) {
              final int[] a = new int[n];
              for (int i = 0; i < n; i++) { a[i] = nextInt(); }
              return a;
          }
  
          long[] nextLongArray(int n) {
              final long[] a = new long[n];
              for (int i = 0; i < n; i++) { a[i] = nextLong(); }
              return a;
          }
      }
  }
  