Problem Description

Define two prime numbers that differ by $2$ as a prime pair, such as $5$ and $7$, $17$ and $19$, etc. The task is to find all prime pairs where both numbers are not greater than $n$.

Input Format

A positive integer $n$. $1 \le n \le 10000$.

Output Format

All prime pairs less than or equal to $n$. Each pair of prime numbers should be printed on a new line, separated by a single space. If no prime pairs are found, output empty.

Sample Input and Output

Sample Input #1

10

Sample Output #1

3 5
5 7

Sample Input #2

100

Sample Output #2

3 5
5 7
11 13
17 19
29 31
41 43
59 61
71 73

Sample Input #3

3

Sample Output #3

empty

见题面 Input 部分

见题面 Output 部分