#include <bits/stdc++.h>
#define rep( i, n ) for (long long i = 0; i < ( long long )(n); i++)

using namespace std;
typedef long long ll;
typedef pair< int , int > P;

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

    rep(i,n+1){
        if(i%3==0||i%5==0) continue;
        else sum+=i;
    }
    cout<<sum;
} 