def afegir_estudiant(dic, nom, cognom1, cognom2, llista):
    dic[(nom, cognom1, cognom2)] = llista

def assignatures_estudiant(dic, nom, cognom1, cognom2):
    if (nom, cognom1, cognom2) not in dic:
        return []
    else:
        return dic[(nom, cognom1, cognom2)]

def llistat(dic,assig):
    ll = []
    for est in dic:
        if assig in dic[est]:
            nomest = est[1] + ' ' + est[2] + ', ' + est[0]
            ll.append(nomest)
    ll.sort()
    return ll

def afegir_assignatures(d, l):

    for x in l:
        if x in d:
            d[x]=d[x] +1
        else:
            d[x] =1

def estudiants_per_assig(dic):
    dassig = {}
    for est in dic:
        lassig = dic[est]
        afegir_assignatures(dassig, lassig)
    return dassig