#include <iostream>
#include <vector>
#include <algorithm>
#include <map>
#include <queue>
#include <cstdio>
#include <ctime>
#include <assert.h>
#include <chrono>
#include <random>
#include <numeric>
#include <set>
using namespace std;
typedef long long int ll;
using ull = unsigned long long;

map<string,int> mp;
vector<int> v(11);
string s="inabameguru";
//set<string> st;

bool ok(char c){
    return (c=='a'||c=='i'||c=='u'||c=='e'||c=='o');
}

void dfs(string t,int n){
    if(n==11&&!mp[t]&&ok(t.back())){
        //st.insert(t);
        cout << t << endl;
        exit(0);
    }
    for(int i=0;i<11;i++){
        if(v[i])continue;
        if(t.size()&&!ok(t.back())&&!ok(s[i]))continue;
        v[i]=1;
        dfs(t+s[i],n+1);
        v[i]=0;
    }
}

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    //freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
    string s="inabameguru";
    int n; cin >> n;
    if(n>=129600){
        printf("NO\n");
        return 0;
    }
    while(n--){
        string t; cin >> t;
        mp[t]=1;
    }
    dfs("",0);
    //printf("%d\n",st.size() );
    printf("NO\n");
}