#include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define MIN(a,b) ((a) <= (b) ? (a) : (b))
#define ALL(v) (v).begin(), (v).end()
#define SORT(v) sort( ALL(v) )

using namespace std;
using ll = long long;
using P = pair<int,int>;


int main()
{

    int n; cin>>n;
    ll sum = 0 ;
    for(int i = 1 ; i<=n ; i++){

        if(i%3 !=0 && i%5!=0)sum+=i;
    }

    cout << sum << endl;

    return 0;
}
