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

typedef long long ll;
static const int MOD = 1e9+7;

int main(){
    ll N;
    cin>>N;
    ll ans = 0;

    for(int i=1; i<=N; i++){
        if(i % 3 == 0 || i % 5 == 0) continue;
        ans += i;
    }

    cout<<ans<<endl;
    
    return 0;
}