#include <iostream>
#include<bits/stdc++.h>

using namespace std;
typedef long long ll;
#define rep(i, n) for(int i = 0; i < (int)(n); i++)


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

    return 0;
}
