#include <iostream>
#include <algorithm>
#include <vector>
#include <stack>
#include <queue>
#include <string>
#include <cmath>
using namespace std;
typedef long long ll;
const ll MOD = 1000000007;
int A[4005]={0};

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

for(int i=1;i<=n;i++){
  if(i%3!=0&&i%5!=0)ans+=i;
}
cout<<ans<<endl;
}