k = list(int(d) for d in str(n))
    for i in range (0, l):
        k[i] = n % 10
        i = i + 1
        n = n / 10
    for x in range (0, l):
        for y in range (0, l):
            if (x != y):
                if (k[x] == k[y]):
                    l = l -1
                    break
    return l