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

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