#include<cstdio>
#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
vector<int> mul(vector<int>&A,int b)
{
    int t=0;
    vector<int>c;
    for(int i=0;i<A.size()||t;i++)
    {
        t=t+A[i]*b;
        c.push_back(t%10);
        t/=10;
    }
    while(c.size()>1&&c.back()==0)  c.pop_back();
    return c;
}
vector<int> div(vector<int>&A,int b)
{
    int t=0;
    vector<int>c;
    for(int i=A.size()-1;i>=0;i--)
    {
        t=t*10+A[i];
        c.push_back(t/b);
        t%=b;
    }
    reverse(c.begin(),c.end());
    while(c.size()>1&&c.back()==0)  c.pop_back();
    return c;
}               //n(n-1)(n-2)(n-3)/24
int main()
{
    int n;
    cin>>n;
    if(n<=3)    
    {
    cout<<"0";
    return 0;
    }
    int x=n;
    vector<int>A;
    vector<int>c;
    while(n)
    {
        A.push_back(n%10);
        n/=10;
    }
    c=A;
    for(int i=x-1;i>=x-3;i--)
    {
    c=mul(c,i);
    }
    c=div(c,24);
    for(int i=c.size()-1;i>=0;i--)  cout<<c[i];
    return 0;
}