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

int main() {
    int n;
    cin >> n;
    ll ans = 0;
    for(int i = 1; i <= n; i++){
        if(i%3==0 || i%5==0) continue;
        else ans+= i;
    }
    cout << ans << endl;
    return 0;
}