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: // https://codeforces.com/problemset/problem/474/F
  
  import java.io.OutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.PrintWriter;
  import java.io.BufferedReader;
  import java.io.InputStreamReader;
  import java.util.*;
  
  public class Main {
      public static void main(String[] args){
          InputStream inputStream = System.in;
          OutputStream outputStream = System.out;
          InputReader in = new InputReader(inputStream);
          PrintWriter out = new PrintWriter(outputStream);
          solve(in, out);
          out.close();
      }
  
      static String reverse(String s) {
          return (new StringBuilder(s)).reverse().toString();
      }
  
      static void sieveOfEratosthenes(int n, int factors[], ArrayList<Integer> ar) 
      { 
          factors[1]=1;
          int p;
          for(p = 2; p*p <=n; p++) 
          { 
              if(factors[p] == 0) 
              { 
                  ar.add(p);
                  factors[p]=p;
                  for(int i = p*p; i <= n; i += p) 
                      if(factors[i]==0)
                          factors[i] = p; 
              } 
          } 
          for(;p<=n;p++){
              if(factors[p] == 0) 
              { 
                  factors[p] = p;
                  ar.add(p);
              } 
          }
      }
  
      static void sort(int ar[]) {
          int n = ar.length;
          ArrayList<Integer> a = new ArrayList<>();
          for (int i = 0; i < n; i++)
              a.add(ar[i]);
          Collections.sort(a);
          for (int i = 0; i < n; i++)
              ar[i] = a.get(i);
      }
  
      static void sort1(long ar[]) {
          int n = ar.length;
          ArrayList<Long> a = new ArrayList<>();
          for (int i = 0; i < n; i++)
              a.add(ar[i]);
          Collections.sort(a);
          for (int i = 0; i < n; i++)
              ar[i] = a.get(i);
      }
  
      static void sort2(char ar[]) {
          int n = ar.length;
          ArrayList<Character> a = new ArrayList<>();
          for (int i = 0; i < n; i++)
              a.add(ar[i]);
          Collections.sort(a);
          for (int i = 0; i < n; i++)
              ar[i] = a.get(i);
      }
  
      static long ncr(long n, long r, long mod) {
          if (r == 0)
              return 1;
          long val = ncr(n - 1, r - 1, mod);
          val = (n * val) % mod;
          val = (val * modInverse(r, mod)) % mod;
          return val;
      }
  
      static int min[];
      static int gcd[];
      static int freq[];
  
      static void build(int a[], int v, int tl, int tr) {
          if (tl == tr) {
              min[v] = a[tl];
              gcd[v] = a[tl];
              freq[v] = 1;
          } else {
              int tm = (tl + tr) / 2;
              build(a, v*2, tl, tm);
              build(a, v*2+1, tm+1, tr);
              if(min[v*2]<min[v*2+1]){
                  min[v] = min[v*2];
                  freq[v] = freq[v*2];
              }
              else if(min[v*2]>min[v*2+1]){
                  min[v] = min[v*2+1];
                  freq[v] = freq[v*2+1];
              }
              else{
                  min[v] = min[v*2];
                  freq[v] = freq[v*2] + freq[v*2+1];
              }
              gcd[v] = (int)gcd(gcd[v*2], gcd[v*2+1]);
          }
      }
  
      // static void update(int v, int tl, int tr, int x, int new_val) {
      //     t1[v] = Math.max(new_val,t1[v]);
      //     if(tl==tr)
      //         return;
      //     int tm = (tl + tr) / 2;
      //     if(x<=tm)
      //         update(t1, v*2, tl, tm, x, new_val);
      //     else
      //         update(t1, v*2+1, tm+1, tr, x, new_val);
      //     min[v] = Math.min(a[v*2],a[v*2+1]);
      //     gcd[v] = (int)gcd(gcd[v*2], gcd[v*2+1]);
      // }
  
      static Pair get(int v, int tl, int tr, int l, int r) {
          if (tl >= l && tr <= r) {
              return new Pair(min[v], freq[v], gcd[v]);
          }
          int tm = (tl + tr) / 2;
          Pair p1 = new Pair(0,0,0);
          Pair p2 = new Pair(0,0,0);
          int f1 = 0, f2 = 0;
          if(l<=tm){
              p1 = get(v*2, tl, tm, l, r);
              f1 = 1;
          }
          if(r>=tm+1){
              p2 = get(v*2+1, tm+1, tr, l, r);
              f2 = 1;
          }
          if(f1==0)
              return p2;
          if(f2==0)
              return p1;
          if(p1.a<p2.a)
              return new Pair(p1.a, p1.b, (int)gcd(p1.c, p2.c));
          if(p1.a>p2.a)
              return new Pair(p2.a, p2.b, (int)gcd(p1.c, p2.c));
          return new Pair(p1.a, p1.b+p2.b, (int)gcd(p1.c,p2.c));
      }
  
      static long max;
  
      static void find(int y[], int z[], int curr, long sum){
          if(curr==-1)
              return;
          if(z[curr]==1){
              if(y[curr]==1){
                  sum = sum*2;
                  find(y,z,curr-1,sum);
              }
              else{
                  sum = sum*2+1;
                  find(y,z,curr-1,sum);
              }
          }
          else{
              if(y[curr]==1){
                  max = Math.min(max,sum*(1<<(curr+1)));
                  return;
              }
              max = Math.min(max,sum*(1<<(curr+1))+(1<<(curr)));
              find(y,z,curr-1,sum*2);
          }
      }
  
      public static void solve(InputReader sc, PrintWriter pw){
          int i, j = 0;
          // int t = 1; 
          long mod = 1000000007;
          int t = sc.nextInt();
          u: while (t-- > 0) {
              int n = sc.nextInt();
              if(n<26){
                  for(i=0;i<n;i++){
                      pw.print((char)(i+'a'));
                  }
                  pw.println();
                  continue u;
              }
              for(i=0;i*2+2<=n;i++);
              i--;
              for(j=0;j<i;j++){
                  pw.print('a');
              }
              pw.print('y');
              for(j=0;j<i+1;j++){
                  pw.print('a');
              }
              if(i*2+2<n){
                  pw.print('z');
              }
              pw.println();
          }
      }
  
      static void KMPSearch(char pat[], char txt[], int pres[])
      {
          int M = pat.length;
          int N = txt.length;
          int lps[] = new int[M];
          int j = 0; 
          computeLPSArray(pat, M, lps);
          int i = 0;
          while (i < N) {
              if (pat[j] == txt[i]) {
                  j++;
                  i++;
              }
              if (j == M) {
                  pres[i-1] = 1;
                  j = lps[j - 1];
              }
              else if (i < N && pat[j] != txt[i]) {
                  if (j != 0)
                      j = lps[j - 1];
                  else
                      i = i + 1;
              }
          }
      }
    
      static void computeLPSArray(char pat[], int M, int lps[])
      {
          int len = 0;
          int i = 1;
          lps[0] = 0; 
          while (i < M) {
              if (pat[i] == pat[len]) {
                  len++;
                  lps[i] = len;
                  i++;
              }
              else 
              {
                  if (len != 0) {
                      len = lps[len - 1];
                  }
                  else
                  {
                      lps[i] = len;
                      i++;
                  }
              }
          }
      }
  
      static void findPrimes(int num, HashMap<Integer, Integer> pos, ArrayList<Integer> ar){
          for(int i=2;i*i<num;i++){
              if(num%i==0){
                  while(num%i==0){
                      num/=i;
                  }
                  if(pos.containsKey(i))
                      continue;
                  ar.add(i);
                  pos.put(i,ar.size()-1);
              }
          }
          if(num>1){
              if(!pos.containsKey(num)){
                  ar.add(num);
                  pos.put(num,ar.size()-1);
              }
          }
      }
  
      static long[][] matrixMult(long a[][], long b[][], long mod){
          int n = a.length;
          int m = a[0].length;
          int p = b[0].length;
          long c[][] = new long[n][p];
          for(int i=0;i<n;i++){
              for(int j=0;j<m;j++){
                  for(int k=0;k<p;k++){
                      c[i][k] += a[i][j]*b[j][k];
                      c[i][k] %= mod;
                  }
              }
          }
          return c;
      }
  
      static long[][] exp(long mat[][], long b, long mod){
          if(b==0){
              int n = mat.length;
              long res[][] = new long[n][n];
              for(int i=0;i<n;i++){
                  res[i][i] = 1;
              }
              return res;
          }
          long half[][] = exp(mat, b/2, mod);
          long res[][] = matrixMult(half, half, mod);
          if(b%2==1){
              res = matrixMult(res, mat, mod);
          }
          return res;
      }
  
      static void countPrimeFactors(int num, int a[], HashMap<Integer,Integer> pos){
          for(int i=2;i*i<num;i++){
              if(num%i==0){
                  int y = pos.get(i);
                  while(num%i==0){
                      a[y]++;
                      num/=i;
                  }
              }
          }
          if(num>1){
              int y = pos.get(num);
              a[y]++;
          }
      }
  
      static void assignAnc(ArrayList<Integer> ar[], int depth[], int sz[], int par[][] ,int curr, int parent, int d){
          depth[curr] = d;
          sz[curr] = 1;
          par[curr][0] = parent;
          for(int v:ar[curr]){
              if(parent==v)
                  continue;
              assignAnc(ar, depth, sz, par, v, curr, d+1);
              sz[curr] += sz[v];
          }
      }
  
      static int findLCA(int a, int b, int par[][], int depth[]){
          if(depth[a]>depth[b]){
              a = a^b;
              b = a^b;
              a = a^b;
          }
          int diff = depth[b] - depth[a];
          for(int i=19;i>=0;i--){
              if((diff&(1<<i))>0){
                  b = par[b][i];
              }
          }
          if(a==b)
              return a;
          for(int i=19;i>=0;i--){
              if(par[b][i]!=par[a][i]){
                  b = par[b][i];
                  a = par[a][i];
              }
          }
          return par[a][0];
      }
  
      static void formArrayForBinaryLifting(int n, int par[][]){
          for(int j=1;j<20;j++){
              for(int i=0;i<n;i++){
                  if(par[i][j-1]==-1)
                      continue;
                  par[i][j] = par[par[i][j-1]][j-1];
              }
          }
      }
  
      static long lcm(int a, int b){
          return a*b/gcd(a,b);
      }
  
      static class Pair1 {
          long a;
          long b;
          
          Pair1(long a, long b) {
              this.a = a;
              this.b = b;
          }
      }
  
      static class Pair implements Comparable<Pair> {
          int a;
          int b;
          int c;
          
          Pair(int a, int b, int c) {
              this.a = a;
              this.b = b;
              this.c = c;
          }
   
          public int compareTo(Pair p) {
              if(a!=p.a)
                  return a-p.a;
              return b-p.b;
          }
      }
  
      static boolean isPrime(int n) { 
          if (n <= 1) 
              return false; 
          if (n <= 3) 
              return true; 
          if (n % 2 == 0 ||  n % 3 == 0) 
              return false; 
          for (int i = 5; i * i <= n; i = i + 6) 
              if (n % i == 0 || n % (i + 2) == 0) 
                  return false; 
          return true; 
      } 
  
      static long gcd(long a, long b) {
          if (b == 0)
              return a;
          return gcd(b, a % b);
      }
  
      static long fast_pow(long base, long n, long M) {
          if (n == 0)
              return 1;
          if (n == 1)
              return base % M;
          long halfn = fast_pow(base, n / 2, M);
          if (n % 2 == 0)
              return (halfn * halfn) % M;
          else
              return (((halfn * halfn) % M) * base) % M;
      }
  
      static long modInverse(long n, long M) {
          return fast_pow(n, M - 2, M);
      }
  
      static class InputReader {
          public BufferedReader reader;
          public StringTokenizer tokenizer;
  
          public InputReader(InputStream stream) {
              reader = new BufferedReader(new InputStreamReader(stream), 9992768);
              tokenizer = null;
          }
  
          public String next() {
              while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                  try {
                      tokenizer = new StringTokenizer(reader.readLine());
                  } catch (IOException e) {
                      throw new RuntimeException(e);
                  }
              }
              return tokenizer.nextToken();
          }
  
          public int nextInt() {
              return Integer.parseInt(next());
          }
  
          public long nextLong() {
              return Long.parseLong(next());
          }
      }
  }