#include <bits/stdc++.h>
using namespace std;

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

