A number is called almost prime if it has exactly two distinct prime divisors. For example, numbers 6, 18, 24 are almost prime, while 4, 8, 9, 42 are not. Find the amount of almost prime numbers which are between 1 and n, inclusive.

Input

Input contains one integer number n (1 ≤ n ≤ 3000).

Output

Output the amount of almost prime numbers between 1 and n, inclusive.

Examples

Input

10


Output

2


Input

21


Output

8
def prime_numbers(limit=3000):
    '''Prime number generator. Yields the series
    2, 3, 5, 7, 11, 13, 17, 19, 23, 29 ...
    using Sieve of Eratosthenes.
    '''
    yield 2
    sub_limit = int(limit**0.5)
    flags = [True, True] + [False] * (limit - 2)
    # Step through all the odd numbers
    for i in range(3, limit, 2):
        if flags[i]:
            continue
        yield i
        # Exclude further multiples of the current prime number
        if i <= sub_limit:
            for j in range(i*i, limit, i<<1):
                flags[j] = True

def divisors(n):
    ct=0
    for num in p:
        if n%num==0:
            ct+=1

    if ct==2:
        return 'y'
    else:
        return 'n'
p=list(prime_numbers())
i=int(raw_input())
ctr=0
for j in range(i+1):
    if divisors(j)=='y':
        ctr+=1
print ctr
