#include <iostream> using namespace std; bool isComposite(int num) { for (int i = 2; i * i <= num; ++i) { if (num % i == 0) return true; } return false; } int main() { int N; cin >> N; int sum = 0; for (int i = 4; i <= N; ++i) { if (isComposite(i)) sum += i; } cout << sum << endl; return 0; }