#include <iostream>
#include<vector>
#include<algorithm>
#include<string>
#include<cmath>
#include<queue>
#include<map>
using namespace std;

#define rep(i,n) for(int i=0;i<n;i++)
typedef long long ll;
typedef pair<int,int> P;

int main(){
    ll n;
    cin >> n;
    ll sum=0;
    for(ll i=1;i<=n;i++){
        if(i%3==0 || i%5==0) continue;
        sum += i;
    }
    cout << sum << endl;
}