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>
int main(void)
{
    int masatoy, kouay, i, k, max1=5, max2=7;
    scanf("%d", &masatoy);
    while (masatoy != 0) {
        for (i = 1; i <= masatoy; i++) {
            if (i!= 1 || i != 2 || i != 3) {
                if (i%2 != 0 && i % 3 != 0 && i % 5 != 0 && i % 7 != 0) {
                    if ((i + 2) % 2 != 0 && (i + 2) % 3 != 0 && (i + 2) % 5 != 0 && (i + 2 )% 7 != 0) {
                        if (max1 < i && masatoy>i+2) {
                            max1 = i;
                            max2 = i + 2;
                        }
                    }
                }

            }
        }
        if(masatoy>5)if(masatoy>max2)printf("%d %d\n", max1,max2);
            scanf("%d", &masatoy);
            max1 = 5;
            max2 = 7;
    }
    return 0;
}