#include <bits/stdc++.h>
using namespace std;

typedef unsigned long long ull;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

#define fastio() ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0)
#define test() int t;cin>>t;for(int test=1;test<=t;test++)
#define pb push_back
#define nl cout<<"\n"
#define F first
#define S second
#define all(x) x.begin(),x.end()

template<class C> void min_self( C &a, C b ){ a = min(a,b); }
template<class C> void max_self( C &a, C b ){ a = max(a,b); }

const ll MOD = 1000000007;
ll mod( ll n, ll m=MOD ){ n%=m,n+=m,n%=m;return n; }

const int MAXN = 1e5+5;
const int LOGN = 21;
const ll INF = 1e14;
int dx[] = {1,0,-1,0};
int dy[] = {0,1,0,-1};

template<class T1, class T2> void add( T1 &x, T2 y, ll m = MOD )
{
    x += y;
    if( x >= m )
        x -= m;
}

template<class T1, class T2> void sub( T1 &x, T2 y, ll m = MOD )
{
    x -= y;
    if( x < 0 )
        x += m;
}

ll divisors( ll n, ll d )
{
    ll lo = 1;
    ll hi = n/d;

    ll sum = ((hi-lo+1)*(lo+hi)*d)/2;
    return sum;
}

int main() 
{
    fastio();

    ll n;
    cin>>n;

    ll total = n*(n+1)/2;

    ll ans = total - divisors(n,3LL) - divisors(n,5LL) + divisors(n,15LL);

    cout<<ans,nl;


    cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
    return 0;
}
