Hey,
Was bored so *TRIED* to make this simple countdown program but i'm just not sure what to put in the for loop?

#include <iostream>
#include <windows.h>

using namespace std;

int main()
{
    int countDown;
    
    cout << "Enter a number to count down from : ";
    cin >> countDown;
    
    for(int i )
    {
            cout << i;
            Sleep(1000);
            system("cls");
    }
}

I've tried int i == countDown etc, but i don't know help please