try: from sympy import factorint
except ImportError: factorint = None

try: range = xrange
except NameError: pass

try: from tqdm import trange
except ImportError: trange = range


from collections import Counter


def multiplicity(n, p):
    i = 0
    while not n % p:
        i += 1
        n = n // p
    return i

def min_factorial(prime, mult):
    cnt = 0

    for i in range(1, mult + 1):
        cnt += multiplicity(i, prime)

        if cnt + i >= mult:
            return prime * i


def min_factorials_sum(m, n, factorize):
    s = 0

    for x in trange(m, n + 1):
        factors = factorize(x)
        s += max(min_factorial(p, m) for p, m in factors.items())

    return s


def factorize(n):
    factors = []
    d = 2

    while d * d <= n:
        while (n % d) == 0:
            factors.append(d)
            n //= d
        d += 1

    if n > 1:
       factors.append(n)

    return Counter(factors)


m, n = 6, 10
result = min_factorials_sum(m, n, factorint or factorize)
print(result)