#include<bits/stdc++.h>
#define F first
#define S second
#define pb push_back
#define mp make_pair
#define full(a) a.begin(),a.end()
#define rfull(a) a.rbegin(),a.rend()

using namespace std;
const double pi=acos(-1.0);
const double pii=2*pi;
const double eps=1e-6;
const long long MOD=1e9+7;

void solve(){
    int n;
    cin>>n;
    long long ans=0;
    for(int i=1;i<=n;i++){
        if(!(i%3==0 || i%5==0)){
            ans+=i;
        }
    }
    cout<<ans<<"\n";
}

int main(){
    std::ios::sync_with_stdio(false);
    std::cin.tie(NULL);
    std::cout.tie(NULL);

    solve();
    return 0;
}