#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
const int inf = 1000000000; 

int main(){
    int n;
    cin >> n;
    ll ans = 0;
    rep(i,n){
        if(i%3 != 0 && i%5 != 0){
            ans += i;
            //cout  << i  << endl;
        }
    }
    cout << ans << endl;
}