l = ['a', 'b', 'c', 'a', 'a', 'd', 'e', 'e', 'e']

def vok(l):
    m = []
    for i in l:
        for j in l:
            if(l[i]=='a' or l[i]=='e' or l[i]=='i' or l[i]=='o' or l[i]=='u'):
                m.append(l[i])
                if(l[j]=='a' or l[j]=='e' or l[j]=='i' or l[j]=='o' or l[j]=='u'):
                    m.append(l[j])
                else:
                    m = []
                    break

    return m

l = vok(l)