#include <bits/stdc++.h>

#define rep(i, n) for(int (i)=0; (i)<(n); (i)++)
#define FILL0(x) memset(x,0,sizeof(x))

using namespace std;

typedef long long ll;
typedef pair<int, int> P;

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
 

int main()
{
    ll N;
 
    cin >> N;
    ll ans=0;
    rep(i, N)
    {
        if(((i+1)%3)!=0&&((i+1)%5)!=0)
        {
            //cout << i+1 << endl;
            ans+=i+1;
        }
    }

 
    cout << ans << endl;
 

    return 0;
}
 

//cout << setprecision(13);
//next_permutation();
//__gcd();
//reverse();
//set ,tuple ,pair;
//bitset
//vector.find

