C :

#include<stdio.h>
int main()
{
    long long ji, n;
    while(scanf("%lld",&n)==1)
    {
        if(n<=2)
        {
            ji = n;
        }
        else if(n%2)
        {
            ji = n*(n-1)*(n-2);
        }
        else
        {
            if(n%3)
            {
                ji = n*(n-1)*(n-3);
            }
            else ji= (n-1)*(n-2)*(n-3);
        }
        printf("%lld\n",ji);
    }
    return 0;
}

C++ :

#include<iostream>
using namespace std;

int main() {
	long long n, ans;
	while(cin >> n) {
		if(n <= 2) {
			ans = n;
		} 
		else if(n % 2) {
			ans = n * (n - 1) * (n - 2);
		}
		else {
			if(n%3) ans = n * (n-1) * (n-3);
			else ans=(n-1) * (n-2) * (n-3);
		}
		cout << ans << endl;
	}
	return 0;
}