Problem:
Twin Prime

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.

Sample Input

12
100
200
300
0

Output for the Sample Input

5 7
71 73
197 199
281 283

Solution in C (judge verdict: Wrong Answer)

#include <stdio.h>
#include <math.h>

int main(void)
{
	int n;
	
	while (scanf("%d", &n) * n != 0){
		int prime[10001] = {0};
		int i, j;
		
		for (i = 2; i <= sqrt(n); i++){
			if (prime[i] == 1) continue;
			for (j = i * 2; j <= n; j += i){
				prime[j] = 1;
			}
		}
		for (i = 2; i <= n; i++){
			if (prime[i] + prime[i + 2] == 0){
				printf("%d %d\n", i, i + 2);
				break;
			}
		}
	}
	
	return 0;
}