448.cpp

#include <cstdio>

bool is_prime(int n) {
    for (int i = 2; i * i <= n; ++i)
        if (n % i == 0) {
            return false;
        }
    return n > 1;
}

int main() {

    int n;
    scanf("%d", &n);

    if (n % 2 == 1) {
        --n;
    }

    while (n > 0) {
        for (int p = n+1; p < n+n; p += 2)
            if (is_prime(p)) {
                int left = p-n;
                int right = n;
                n = left-1;
                while (left < right) {
                    printf("%d %d\n", left, right);
                    ++left;
                    --right;
                }
                break;
            }
    }

    return 0;
}