import copy
N = int(input())
S = []
candi = set()
for _ in range(N):
    s=input()
    candi.add(s)
s = ["n","b","m","g","r"]
b = ["i","a","a","e","u","u"]
#print(candi)
s5=[]
b6=[]

for i in range(6):
    if i<5:
        s5.append(i)
    b6.append(i)

import itertools
ss = list(itertools.permutations(s5,5))
bb = list(itertools.permutations(b6,6))
#print(ss)
flag=False
for i in ss:
    c = [[] for _ in range(16)]
    #print(c[0])
    #print(s[i[0]])
    for j in bb:
        c[1] = (s[i[0]])
        c[4] = (s[i[1]])
        c[7] = (s[i[2]])
        c[10] = (s[i[3]])
        c[13] = (s[i[4]])
        c[2] = (b[j[0]])
        c[5] = (b[j[1]])
        c[8] = (b[j[2]])
        c[11] = (b[j[3]])
        c[14] = (b[j[4]])
        #cc=c.copy()
        cc=copy.deepcopy(c)
        for k in range(0,16,3):
            cc[k]=b[j[5]]
            candidate = ""
            #print(cc)
            for ccc in cc:
                if not ccc==[]:
                    #print(ccc)
                    candidate+=ccc
            #print(candidate)
            if candidate not in candi:
                print(candidate)
                exit()

print("No")