#include<bits/stdc++.h>
bool f(int x){
	if(x<2)
        return false;
	for(int i=2;i*i<=x;i++)
		if(x%i==0)
            return false;
	return true;
}
using namespace std;
int main(){
	int a,s=0;
    cin>>a;
	for(int i=1;i<=a;++i)
		if(f(i-2)&&f(i)){
            s++;
            cout<<i-2<<" "<<i<<endl;
        }
	if(s==0)
        cout<<"empty";
	return 0;
}

#include #include using namespace std;

int main() { int n; cin >> n;

if (n < 5) {
    cout << "empty" << endl;
    return 0;
}

// 筛素数
vector<bool> is_prime(n + 1, true);
is_prime[0] = is_prime[1] = false;
for (int i = 2; i * i <= n; i++) {
    if (is_prime[i]) {
        for (int j = i * i; j <= n; j += i) {
            is_prime[j] = false;
        }
    }
}

bool found = false;
for (int i = 2; i <= n - 2; i++) {
    if (is_prime[i] && is_prime[i + 2]) {
        cout << i << " " << i + 2 << endl;
        found = true;
    }
}

if (!found) {
    cout << "empty" << endl;
}

return 0;

}