p00009 Prime Number
Write a program which reads an integer n and prints the number of prime numbers which are less than or equal to n. A prime number is a natural number which has exactly two distinct natural number divisors: 1 and itself. For example, the first four prime numbers are: 2, 3, 5 and 7.



Input

Input consists of several datasets. Each dataset has an integer n (1 ≤ n ≤ 999,999) in a line.

The number of datasets is less than or equal to 30.

Output

For each dataset, prints the number of prime numbers.

Example

Input

10
3
11


Output

4
2
5
```python
import sys
import math


LIMIT = 1000000
p = 2
pList = [True] * (LIMIT + 1)


while p ** 2 <= LIMIT:
    if(pList[p]):
        for i in range(p * 2, LIMIT + 1 , p):
            pList[i] = False
    p += 1

# print(pList)


lines = str(sys.stdin.read()).strip().split("\n")

for line in lines:
    line = int(line)
    count = 0
    for i in range(2, line + 1):
        if pList[i]:
            count += 1
    print(count)
```