#include <bits/stdc++.h>
using namespace std;
int main() {
    int64_t n;
    cin>>n;
    int64_t sum=0;
    for(int i=1;i<=n;i++){
        if(i%3==0 ||i%5==0){
            continue;
        }else{
            sum+=i;
        }
    }
    cout<<sum<<endl;
}