//agrawal117
//chahatagrawal117
#include<bits/stdc++.h>
#define endl '\n'
#define mod 1000000007
typedef long long int ll;
using namespace std;
#define MAX 100005
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    ll 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;
}