#include <iostream>
using namespace std;

typedef long long ll;

int main(void){
   ll N, sum;
   
   cin >> N;
   sum = 0;
   for(ll i = 1; i < N; i++){
       if((i%3) != 0 && (i%5) != 0){
           sum += i;
       }
   }

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