#include <iostream> using namespace std; bool isPerfect(int num) { int sum = 1; // 1 is always a factor for (int i = 2; i * i <= num; ++i) { if (num % i == 0) { sum += i; if (i != num / i) sum += num / i; } } return sum == num; } int main() { int n; cin >> n; for (int i = 2; i <= n; ++i) { if (isPerfect(i)) cout << i << endl; } return 0; }