federica file

def f(file):
    file = open(file,"r")
    righe = file.readlines()
    d = {}
    for riga in righe:
        parole = riga.strip().split()
        for parola in parole:
            for c in parola:
                if c in d:
                    d[c] += 1
                else:
                    d[c] = 1

    massimo = 0

    l = []

    for k in d:
        l.append(d[k])

    l.sort()
    print(l[len(l) - 3])

f("test.txt")