#include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < n; ++i)
using namespace std;

int main(){
    int N;
    cin >> N;
    int sum = 0;
    int i;
    for(i=1;i<N; i++){
        if(i%3 != 0 && i%5 != 0){
            sum += i;
        }
    }

    cout << sum << endl;
}