hdu1262

/**/
#include <cstdio>
#include <cstring>
#include <cmath>
#include <cctype>
#include <iostream>
#include <algorithm>
#include <map>
#include <set>
#include <vector>
#include <string>
#include <stack>
#include <queue>

typedef long long LL;
using namespace std;

int prime[10005], vis[10005];

void init(){
	for (int i = 2; i <= 10000; i++){
		if(!vis[i]){
			prime[++prime[0]] = i;
		}
		for (int j = 1; j <= prime[0] && i * prime[j] <= 10000; j++){
			vis[i * prime[j]] = 1;
			if(i % prime[j] == 0) break;
		}
	}
}

int main()
{
	//freopen("in.txt", "r", stdin);
	//freopen("out.txt", "w", stdout);

	init();
	int n;
	while(scanf("%d", &n) == 1){
		int mid = (n >> 1);
		for (int i = mid; i >= 2; i--){
			if(!vis[i] && !vis[n - i]){
				printf("%d %d\n", i, n - i);
				break;
			}
		}
	}

	return 0;
}
/**/

虽然数据很小，但是我还是用了线筛，当做模板吧！