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

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