import re


def merge_acronyms(s):
    """Merges all acronyms in a given sentence. For example M.I.T -> MIT"""
    r = re.compile(r'(?:(?<=\.|\s)[A-Z]\.)+')
    acronyms = r.findall(s)
    for a in acronyms:
        s = s.replace(a, a.replace('.',''))
    return s