import re
def mendeleev(bestand):
    mendel = dict()
    sub = []
    sub1 = ""
    sub2 = ""
    with open(bestand) as file:
        data = file.read()
        ls = data.split("\n")
        for i in range(len(ls) - 1):
            sub = ls[i].split()
            sub1 = sub[0]
            sub2 = sub[1]
            mendel[sub1] = sub2
    return mendel

def aantalcombi(strd):
    aantal = 0
    for i in strd:
        if i.isupper():
            aantal += 0
    return aantal
def symbols(symbolen):
    ls = re.findall('[A-Z][a-z]*', symbolen)
    return ls

def encode(letters, ls):
    strd = ""
    letters = symbols(letters)
    for i in letters:
        if i in ls:
            strd += ls[i] + " "
        else:
            raise AssertionError("invalid symbol")
    strd = strd.rstrip()
    return strd


def decode(zin, ls):
    zin = zin.split()
    elementen = ""
    for i in zin:
        if i in ls.values():
            for j, k in ls.items():
                if i == k:
                    elementen += j
        else:
            raise AssertionError("invalid name")
    return elementen