题目描述
Prime numbers are widely applied for cryptographic and communication technology. A twin prime is a prime number that differs from another prime number by 2. For example, (5, 7) and (11, 13) are twin prime pairs.
In this problem, we call the greater number of a twin prime "size of the twin prime."
Your task is to create a program which reads an integer n and prints a twin prime which has the maximum size among twin primes less than or equals to n
You may assume that 5 ≤ n ≤ 10000.
Input
The input is a sequence of datasets. The end of the input is indicated by a line containing one zero. Each dataset is formatted as follows:
n (integer)
Output
For each dataset, print the twin prime p and q (p < q). p and q should be separated by a single space.
Example
Input
12
100
200
300
0
Output
5 7
71 73
197 199
281 283
输入格式
见题面
输出格式
见题面