#include <bits/stdc++.h>
#define rep(i,n) for (int i=0; i<(n); ++i)
using namespace std;
using ll=long long;
int main(){
    int n;
    cin>>n;
    ll sum=0;
    for(int i=1; i<=n; ++i){
        if(i%3!=0&&i%5!=0)sum+=i;
    }
    cout<<sum<<endl;
}
