import collections
import string

def retrieveMostFrequentlyUseWords(helpText, wordsToExclude):
    wordsToExclude = set([item.lower() for item in wordsToExclude])

    helpText = helpText.lower()
    exclude = set(string.punctuation)
    helpText = ''.join(ch if ch not in exclude else " " for ch in helpText).split()

    c = collections.Counter()
    for word in helpText:
        c[word] += 1

    for sym in wordsToExclude:
        if sym in c:
            c.pop(sym)

    most_common = c.most_common()
    most_frequent = []
    if not len(most_common):
        return []
    max_n = most_common[0][1]
    most_frequent.append(most_common[0][0])
    for i in range(1, len(most_common)):
        if most_common[i][1] < max_n:
            return most_frequent
        most_frequent.append(most_common[i][0])
    return most_frequent