#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef long double ld;
typedef vector<ll> vl;
typedef vector<string> vs;
typedef vector<char> vc;
typedef queue<ll> ql;
typedef deque<ll> dql;
typedef priority_queue<ll, vl/*, greater<ll>*/> pql; //降順(/*昇順*/)
typedef set<ll> sl;
#define rep(i, n) for(ll i = 0; i < ll(n); i++)
#define rep2(i, n) for(ll i = 1; i <= ll(n); i++)
//#define rep(i, k, n) for(ll i = k-1; i < ll(n); i++)
//#define rep2(i, k, n) for(ll i = k; i <= ll(n); i++)
#define all(v) (v).begin(), (v).end()
bool chmin(ll &a, ll &b) {if(b < a) {a = b; return 1;} return 0;}
bool chmax(ll &a, ll &b) {if(b > a) {a = b; return 1;} return 0;}
const ll INF = 1LL << 60;
const ll MOD = 1e9 + 7;
//const ll MOD = 998244353;
const ll MAX = 1e9;
ll num=1, ans=0, count=0, sum=0;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  ll N;
  cin >> N;
  rep2(i, N) {
    if(i%3!=0 && i%5!=0) sum += i;
  }
  cout << sum << '\n';
  return 0;
}