Python 3.5, Finding user inputted values in a set and displaying them

from collections import Counter

inp = input("Please enter some text: ")
vowels = set("aeiouAEIOU")

if inp in vowels:
    res = Counter(c for c in inp if c in vowels)
    print (res.most_common())

elif inp not in vowels:
    print("No vowels entered.")

Code is meant to output vowels if any are found in the users input or if there are none, print a message. Currently the code does not work if more than one vowel in inputted by the user as it print the line "No vowels entered". How can this fault be corrected.