#ifdef BUILT_LOCAL

#include "niklib.h"

#endif

#include <iostream>
#include <utility>
#include <numeric>
#include <vector>
#include <stack>
#include <queue>
#include <algorithm>
#include <string>
#include <cstdio>
#include <map>
#include <cmath>
#include <set>
#include <list>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef __int128 lll;
constexpr ll mod = 1000000007;

#define bs(n) (1ull<<(ull)(n))
#define rep(i, n) for(ll (i) = 0;(i) < (n);(i)++)

int main() {
    ll s = 0, n;
    cin >> n;
    rep(i, n) {
        ll t = i + 1;
        if (t % 3 && t % 5)s += t;
    }
    cout << s << endl;
}
