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

int main(){
    long long n,sum=0;
    cin >> n;
    for(long long i = 1 ; i <= n ; i += 1){
        if(i % 3 == 0 || i % 5 == 0){
            continue;
        }
        sum += i;
    }
    cout << sum << endl;
}