#include <iostream>
 
using namespace std;
 
int main()
{
  int i, n;
 
  // read n from the user
 
  cin >> n;
 
  // print out all numbers <=n that are divisible by 3
 
  // approach 1
 
  cout << "Approach 1:" << endl;
 
  for (i = 1; i <= n; i++)
    if (i%3 == 0)
       cout << i << endl;
 
  // approach 2
 
  cout << "Approach 2:" << endl;
 
  for (i = n; i > 0; i--)
    if (i%3 == 0)
       cout << i << endl;
 
  // approach 3
 
  cout << "Approach 3:" << endl;
 
  for (i = 3; i <= n; i+=3)
    cout << i << endl;
 
  // approach 4
 
  cout << "Approach 4:" << endl;
 
  for (i = n-n%3; i > 0; i-=3)
    cout << i << endl;
 
  return 0;
}

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