Что выведет код?

def f(seq):
    if not seq:  
        return [seq]
    else:
        res = []
        for i in range(len(seq)):
            rest = seq[:i] + seq[i+1:] 
            for x in f(rest):
                res.append(seq[i:i+1] + x)
        return res
a = f([1, 2])
b = f([1, 2, 3, 4, 5])
print(a, len(b))