#include <iostream>
using namespace std;
int main()
{
	int A[30] = {};
	int P[1000000] = {};
	int i = 0, k;
	while (cin >> k) A[i++] = k;
	int c = 0, j;
	for (int k = 2; k < 1000000; ++k){
		if (P[k] == 0){
			P[k] = ++c;
			for (j = 2; j * k < 1000000; ++j)
				P[j * k] = -1;
		}
		else if (P[k] == -1)
			P[k] = c;		
	}
	for (j = 0; j < i; ++j)
		cout << P[A[j]] << "\n";
	return 0;
}
### Prompt

Your task is to create a CPP solution to the following problem:

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

### Response

```cpp
#include <iostream>
using namespace std;
int main()
{
	int A[30] = {};
	int P[1000000] = {};
	int i = 0, k;
	while (cin >> k) A[i++] = k;
	int c = 0, j;
	for (int k = 2; k < 1000000; ++k){
		if (P[k] == 0){
			P[k] = ++c;
			for (j = 2; j * k < 1000000; ++j)
				P[j * k] = -1;
		}
		else if (P[k] == -1)
			P[k] = c;		
	}
	for (j = 0; j < i; ++j)
		cout << P[A[j]] << "\n";
	return 0;
}
```