#include<bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(n);i++)
#define loop(i,x,n) for(int i=(x);i<(n);i++)
#define all(x) (x).begin(),(x).end()
#define pb push_back
#define mp make_pair
#define fir first
#define sec second
#define ub upper_bound
#define lb lower_bound
#define int long long
using namespace std;
const int MOD=1000000007;
const int INF=1000000009;



signed main(){
  int n;
  while(cin>>n){
    int ans=0;
    rep(i,1000){
      rep(j,1000){
        rep(k,1000){
          if(i+j+k<=n&&i+j+k>=n-1000)ans++;
          if(i+j+k>n)break;
        }
        if(i+j>n)break;
      }
      if(i>n)break;
    }
    cout<<ans<<endl;
  }
  return 0;
}