#include<bits/stdc++.h>
#define int long long
using namespace std;
int n,ans[10000005],a[10000001],j[1000001]; 
signed main(){
    freopen("TricountUVa.in","r",stdin);
    freopen("TricountUVa.out","w",stdout);
    ans[3]=0;
    ans[4]=1;
    ans[5]=3;
    a[3]=a[4]=1;
    j[3]=j[4]=0;
    j[5]=2;
    for(int i=5;i<=100;i++){
        a[i]=a[i-1];
        if(i%2==1){
            a[i]++;
        }
    }
    for(int i=6;i<=100;i++){
        j[i]=j[i-1]+a[i-1];
    }
    for(int i=5;i<=10;i++){
        ans[i]=ans[i-1]+j[i]; 
    }
    while(cin>>n&&n>=3){
        cout<<ans[n]<<endl;
    }
    return 0;
}