#include <bits/stdc++.h>
#define max(x, y) ((x) > (y) ? (x) : (y))
#define min(x, y) ((x) < (y) ? (x) : (y))
#define rep(i,a,m) for((i) = (a) ; (i) < (m) ; ++(i))
#define REP(i,n) for((i)=0;(i)<(int)(n);(i)++)
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define all(x) x.begin(),x.end()
#define rall(x) x.end(),x.begin()
#define sz(x) ((int)x.size())
using namespace std;
/*
#ifdef JUDGE
#include <fstream>
std::ifstream cin("input.txt");
std::ofstream cout("output.txt");
#else
#include <iostream>
using std::cin;
using std::cout;
#endif
*/
typedef unsigned long long ull;
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<vi> vvi;
typedef vector<vl> vvl;
typedef pair<int,int> pi;
int a, b, c, i, j, k;
long long ans = 0LL;
long double eps = 1.0E-14;
long long MOD = 1000000007;
int main ()
{
	ios::sync_with_stdio(0);
	cin.tie(0);
	ll t,T;
	cin >> T;	
    long long sum = (T*(T+1))/2;
    ll t3 = T/3, t5 = T/5, t15 = T/15;
    sum -= 3LL*((t3*(t3+1))/2);
    sum -= 5LL*((t5*(t5+1))/2);
    sum += 15LL*((t15*(t15+1))/2);
    cout << sum << endl;
	return 0;
}