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
import math as mt 
  
MAXN = 3001
  
# stores smallest prime factor for 
# every number 
spf = [0 for i in range(MAXN)] 
  
# Calculating SPF (Smallest Prime Factor)  
# for every number till MAXN. 
# Time Complexity : O(nloglogn) 
def sieve(): 
    spf[1] = 1
    for i in range(2, MAXN): 
          
        # marking smallest prime factor  
        # for every number to be itself. 
        spf[i] = i 
  
    # separately marking spf for  
    # every even number as 2 
    for i in range(4, MAXN, 2): 
        spf[i] = 2
  
    for i in range(3, mt.ceil(mt.sqrt(MAXN))): 
          
        # checking if i is prime 
        if (spf[i] == i): 
              
            # marking SPF for all numbers 
            # divisible by i 
            for j in range(i * i, MAXN, i):  
                  
                # marking spf[j] if it is  
                # not previously marked 
                if (spf[j] == j): 
                    spf[j] = i 
  
# A O(log n) function returning prime  
# factorization by dividing by smallest  
# prime factor at every step 
def getFactorization(x): 
    ret = list() 
    while (x != 1): 
        ret.append(spf[x]) 
        x = x // spf[x] 
  
    return ret 
  
# Driver code 
  
# precalculating Smallest Prime Factor 
sieve() 
n = int(input())
numberOfAlmostPrimeTill_n = 0
for i in range(1,n+1):
    primes = getFactorization(i)
    primes = list(set(primes))
    if len(primes)==2:
        numberOfAlmostPrimeTill_n+=1
print(numberOfAlmostPrimeTill_n)