/*
--> WHEN IT'S OBVIOUS THAT THE GOAL CANNOT BE REACHED,
	DON'T ADJUST THE GOALS,
	ADJUST THE ACTION STEPS.

--> THE WAY YOU CONQUER SELF-DOUBT IS BY DOING THINGS THAT MAKE YOU UNCOMFORTABLE.

--> IT IS DURING OUR DARKEST MOMENTS WE MUST FOCUS TO SEE LIGHT.
*/

#include <iostream>
#include <iomanip>
#include <vector>
#include <set>
#include <map>
#include <string>
#include <stack>
#include <queue>
#include <unordered_map>
#include <algorithm>
#include <numeric>
#include <cmath>
#include <cstring>
#include <climits>
using namespace std;
#define pb push_back
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define sortAll(x) sort(all(x))
#define sz(x) (int)x.size()
#define clr(x) memset(x, 0, sizeof(x))
#define PI 3.1415926535897932384626
#define FAST ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); IO();
typedef long long ll;
typedef pair< int, int >	pii;
typedef pair< ll, ll >		pl;
typedef vector< int >		vi;
typedef vector< ll >		vl;
typedef vector< pii >		vpii;
typedef vector< pl >		vpl;
typedef vector< vi >		vvi;
typedef vector< vl >		vvl;

const int MOD = 1e9 + 7;

ll power(ll a, ll b)
{
	ll ans = 1;

	while (b > 0)
	{
		if (b & 1)
			ans *= a;
		a = a * a;
		b >>= 1;
	}
	return ans;
}

ll powm(ll a, ll b)
{
	a %= MOD;
	ll ans = 1;

	while (b > 0)
	{
		if (b & 1)
			ans = (ans * a) % MOD;
		a = (a * a) % MOD;
		b >>= 1;
	}
	return ans;
}

void IO()
{
	#ifndef ONLINE_JUDGE
		freopen("Input.txt", "r", stdin);
		freopen("Output.txt", "w", stdout);
	#endif
}

//================================

int main()
{
	FAST;

	ll n;
	cin >> n;

	ll i = 1, ans = 0;
	while (n--)
	{
		if (i % 3 != 0 && i % 5 != 0)
			ans += i;
		i++;
	}
	cout << ans << "\n";
	return 0;
}