#include <iostream> using namespace std; bool isComposite(int num) { if (num < 4) return false; 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; }