import java.io.BufferedReader;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.LinkedList;
import java.util.Scanner;
import java.util.Set;
import java.util.StringTokenizer;
import java.util.TreeSet;

public class Main {
	
	public static boolean is_vowel(char c){
		return c == 'a' || c == 'i' || c == 'u' || c == 'e' || c == 'o';
	}
	
	public static void dfs(final int deep, char[] input, StringBuilder builder, boolean[] used, HashSet<String> result){
		final char prev = builder.length() == 0 ? 'i' : builder.charAt(builder.length() - 1);
		
		if(deep >= input.length){
			//System.out.println(builder);
			result.add(builder.toString());
			return;
		}
		
		int can_use_vovel = 0, can_use_not_vovel = 0;
		for(int i = 0; i < input.length; i++){
			if(!used[i]){
				if(is_vowel(input[i])){
					can_use_vovel++;
				}else{
					can_use_not_vovel++;
				}
			}
		}
		if(can_use_vovel < can_use_not_vovel){ return; }
		
		for(int next = 0; next < input.length; next++){
			if(used[next]){ continue; }
			if(!is_vowel(prev) && !is_vowel(input[next])){ continue; }
			if(deep == input.length - 1 && !is_vowel(input[next])){ continue; }
			
			used[next] = true;
			builder.append(input[next]);
			
			dfs(deep + 1, input, builder, used, result);
			
			builder.deleteCharAt(builder.length() - 1);
			used[next] = false;
		}
	}
	
	public static void main(String[] args) throws IOException {
		Scanner sc = new Scanner(System.in);
		
		final String meguru = "inabameguru";
		
		final int N = sc.nextInt();
		
		HashSet<String> result = new HashSet<String>();
		dfs(0, meguru.toCharArray(), new StringBuilder(), new boolean[meguru.length()], result);
		
		for(int i = 0; i < N; i++){
			result.remove(sc.next());
		}
		
		if(result.isEmpty()){
			System.out.println("NO");
		}else{
			for(String s : result){
				System.out.println(s);
				break;
			}
		}	
	}
	
	public static class Scanner implements Closeable {
		private BufferedReader br;
		private StringTokenizer tok;
 
		public Scanner(InputStream is) throws IOException {
			br = new BufferedReader(new InputStreamReader(is));
		}
 
		private void getLine() throws IOException {
			while (!hasNext()) {
				tok = new StringTokenizer(br.readLine());
			}
		}
 
		private boolean hasNext() {
			return tok != null && tok.hasMoreTokens();
		}
 
		public String next() throws IOException {
			getLine();
			return tok.nextToken();
		}
 
		public int nextInt() throws IOException {
			return Integer.parseInt(next());
		}
 
		public long nextLong() throws IOException {
			return Long.parseLong(next());
		}
 
		public void close() throws IOException {
			br.close();
		}
	}	
}