Contest1292/D.cpp

#include<bits/stdc++.h>
using namespace std;
bool prime(int n){
    if(n <= 1)return false;
    if(n == 2)return true;
    if(n % 2 == 0)return false;
    for(int i = 3; i * i <= n; i+= 2){
        if( n % i == 0){
            return false;
        }
    }
    return true;
}
int main(){
    int n;
    cin >> n;
    if(n % 2 == 0){
        n -= 2;
        cout << 2;
    }else{
        n -= 3;
        cout << 3;
    }
    for(int i = 2; 2 * i <= n; i++){
        if(prime(i) and prime(n - i)){
            cout << ' ' << i << ' ' << n - i << endl;
            break;
        }
    }
    return 0;
}