#include <bits/stdc++.h>
#define REP(i,n) for(int i=0;i<(n);++i)
using namespace std;
typedef long long LL;

int main() {
  int N;
  cin >> N;
  LL sum = 0;
  for(int i=1; i<=N; ++i) {
    if(i % 3 == 0 || i % 5 == 0) continue;
    sum += i;
  }
  cout << sum << endl;
} 