import re


def getaaNum(protein):
    """
    get the amino acid number from a given protein

    ex: p.Thr141Met -> 141
    """
    pattern = re.compile(r'[1-9][0-9][0-9][0-9]|[1-9][0-9][0-9]|[1-9][0-9]|[1-9]')
    result = pattern.findall(protein)
    result = result[0]
    return(result)