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 Python (judge verdict: Time Limit Exceeded)

while True:
    N = input()
    if N == 0: break
    L = ['' for i in range(N-1)]
    L.insert(0, '*')
    for i, v in enumerate(L):
        n = i+1
        if v == '':
            for i in range(n*2-1, len(L), n):
                L[i] = '*'
    prime = []
    for i, v in enumerate(L):
        if v == '':
            prime.append(i+1)
    prime.reverse()
    for i in range(len(prime)):
        if prime[i]-prime[i+1] == 2:
            print prime[i+1], prime[i]
            break