import java.util.*;
import java.io.*;
public class Main
{
static ArrayList<String> arr = new ArrayList<>();
static void gen()
{
for(int i = 0; i<26; i++)
{
arr.add(nextChar(i)+"");
}
for(int i = 0; i<26; i++)
{
for(int j = 0; j<26; j++)
{
arr.add(nextChar(i)+""+nextChar(j));
}
}
for(int i = 0; i<26; i++)
{
for(int j = 0; j<26; j++)
{
for(int k = 0; k<26; k++)
{
arr.add(nextChar(i)+""+nextChar(j)+""+nextChar(k));
}
}
}
// Collections.sort(arr);
}
static char nextChar(int n)
{
return (char)(n+'a');
}
{
// Scanner read = new Scanner(System.in);
gen();
// for(int i = 0; i<100; i++)
// {
// System.out.println(arr.get(i));
// }
int tc = read.nextInt();
for(int cs = 1; cs<=tc; cs++)
{
int n = read.nextInt();
for(int i = 0; i<arr.size(); i++)
{
if(!s.contains(arr.get(i)))
{
System.
out.
println(arr.
get(i
)); break;
}
}
}
}
}
{
final private int BUFFER_SIZE = 1 << 16;
private byte[] buffer;
private int bufferPointer, bytesRead;
{
buffer = new byte[BUFFER_SIZE];
bufferPointer = bytesRead = 0;
}
{
buffer = new byte[BUFFER_SIZE];
bufferPointer = bytesRead = 0;
}
{
byte[] buf = new byte[10000]; // line length
int cnt = 0, c;
while ((c = read()) != -1)
{
if (c == '\n')
break;
buf[cnt++] = (byte) c;
}
return new String(buf,
0, cnt
); }
{
int ret = 0;
byte c = read();
while (c <= ' ')
c = read();
boolean neg = (c == '-');
if (neg)
c = read();
do
{
ret = ret * 10 + c - '0';
} while ((c = read()) >= '0' && c <= '9');
if (neg)
return -ret;
return ret;
}
{
long ret = 0;
byte c = read();
while (c <= ' ')
c = read();
boolean neg = (c == '-');
if (neg)
c = read();
do {
ret = ret * 10 + c - '0';
}
while ((c = read()) >= '0' && c <= '9');
if (neg)
return -ret;
return ret;
}
{
double ret = 0, div = 1;
byte c = read();
while (c <= ' ')
c = read();
boolean neg = (c == '-');
if (neg)
c = read();
do {
ret = ret * 10 + c - '0';
}
while ((c = read()) >= '0' && c <= '9');
if (c == '.')
{
while ((c = read()) >= '0' && c <= '9')
{
ret += (c - '0') / (div *= 10);
}
}
if (neg)
return -ret;
return ret;
}
{
bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
if (bytesRead == -1)
buffer[0] = -1;
}
{
if (bufferPointer == bytesRead)
fillBuffer();
return buffer[bufferPointer++];
}
{
if (din == null)
return;
din.close();
}
}