#include<iostream>
#include<iomanip>
#include<math.h>
using namespace std;

int main(){
    int64_t i;//preparation for
    int64_t n;
    int64_t s;

    cin>>n;
    s=0;

    for(i=1;i<=n;i++){
        if(i%3!=0&&i%5!=0){
            s+=i;
        }
    }

    cout<<s;
    return 0;
}