#include <bits/stdc++.h>
using namespace std;
#define all(x) x.begin(),x.end()
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
template<class T> inline bool chmax(T&a,T b){if(a<b){a=b;return 1;}return 0;}
template<class T> inline bool chmin(T&a,T b){if(a>b){a=b;return 1;}return 0;}
using ll = long long;
using P = pair<int,int>;

ll n,m,sum;
string s,t;

int main() {
  cin >> n;
  rep(i,n)if((i+1)%3!=0 && (i+1)%5!=0) sum+=i+1;
  cout << sum << endl;
}