#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using vi = vector<int>;
using vl = vector<ll>;

int main(){
    ll N;
    cin >> N;
    ll sum = 0;
    for(int i = 1; i <= N; i++){
        sum += i;
    }
    for(int i = 1; i <= N; i++){
        if(i % 3 == 0){
            sum -= i;
        }
        if(i % 5 == 0){
            sum -= i;
        }
        if(i % 3 == 0 && i % 5 == 0){
            sum += i;
        }
    }
    cout << sum << endl;
    return 0;
}