package no233;

import java.util.Arrays;
import java.util.HashSet;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		char[] p = "inabameguru".toCharArray();
		Arrays.sort(p);
		int l = p.length;
		HashSet<String> anagram = new HashSet<>();
		LOOP: do {
			if (!isBoin(p[l-1])) {
				continue;
			}
			boolean siin = false;
			for(int i=0;i<l;i++) {
				if (isBoin(p[i])) {
					siin = false;
				}else{
					if (siin) {
						continue LOOP;
					}
					siin = true;
				}
			}
			anagram.add(new String(p));
		} while(nextPermutation(p));

		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		for(int i=0;i<n;i++) {
			anagram.remove(sc.next());
		}
		if (anagram.isEmpty()) {
			System.out.println("NO");
		}else{
			System.out.println(anagram.iterator().next());
		}

	}
	static boolean isBoin(char c) {
		return c == 'a' || c == 'i' || c == 'u' || c == 'e';
	}
	static boolean nextPermutation(char[] p) {
		for(int a=p.length-2;a>=0;--a) {
			if(p[a]<p[a+1]) {
				for(int b=p.length-1;;--b) {
					if(p[b]>p[a]) {
						char t = p[a];
						p[a] = p[b];
						p[b] = t;
						for(++a, b=p.length-1;a<b;++a,--b) {
							t = p[a];
							p[a] = p[b];
							p[b] = t;
						}
						return true;
					}
				}
			}
		}
		return false;
	}
}