#include <bits/stdc++.h>
#define rep(i, n)  for (int i = 0; i < (n); ++i )
using namespace std;
using ll = long long;
using P = pair<int, int>;

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