#include <bits/stdc++.h>
using namespace std;
// clang-format off

using LL = long long;
#define COUT(x) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << endl

#define REP(i,x) for(int i=0;i<(int)(x);i++)
#define FOR(i,c) for(__typeof((c).begin())i=(c).begin();i!=(c).end();i++)
#define RFOR(i,c) for(__typeof((c).rbegin())i=(c).rbegin();i!=(c).rend();i++)
#define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() );
 
template<class T> ostream& operator<<(ostream &os, const vector<T> &t) {
os<<"["; FOR(it,t) {if(it!=t.begin()) os<<","; os<<*it;} os<<"]"; return os;
}
template<class T> ostream& operator<<(ostream &os, const set<T> &t) {
os<<"{"; FOR(it,t) {if(it!=t.begin()) os<<","; os<<*it;} os<<"}"; return os;
}
template<class S, class T> ostream& operator<<(ostream &os, const pair<S,T> &t) { return os<<"("<<t.first<<","<<t.second<<")";}
// clang-format on

void solve(long long N) {
  // solver code

  LL sum = 0;
  for (int i = 0; i < N; i++) {
    if ((i % 3) != 0 && (i % 5) != 0) {
      sum += i;
    }
  }

  cout << sum << endl;
}

int main() {
  long long N;
  scanf("%lld", &N);
  solve(N);
  return 0;
}
