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

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