import sys

def sieve(n):
    sieve = [True] * (n + 1)
    sieve[0] = sieve[1] = False
    for i in range(2, int(n ** 0.5) + 1):
        if sieve[i]:
            sieve[i*i : n+1 : i] = [False] * len(sieve[i*i : n+1 : i])
    primes = [i for i, is_prime in enumerate(sieve) if is_prime]
    return primes

# Generate primes up to 2e6 to cover the first 1e5 primes
primes = sieve(2000000)

N, M = map(int, sys.stdin.readline().split())

if M > len(primes):
    print(0)
else:
    p = primes[M - 1]
    print(N // p)