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

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