#include<bits/stdc++.h>
using namespace std;

int N;

int main(){
 cin >> N;
 long long sum = 0;

 for(int i = 1; i <= N; i++){
   if(i % 3 == 0 || i % 5 == 0) continue;
   else sum += i;
 }

 cout << sum << endl;
 return 0;
}


  