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

    int n;
    cin>>n;

    long long sum=0;

    rep(i,n+1){
        if(i%3!=0&&i%5!=0){sum+=i;}
    }

cout<<sum<<endl;

}