#include<iostream>
#include<vector>
#include<algorithm>
#include<string>
#include<queue>
#include<cmath>
#include<cstdio>
#include<tuple>
#include<bitset>

using namespace std;
#define int long long
#define rep(i,n) for(int i=0;i<n;++i)
#define rep1(i,n) for(int i=1;i<=n;++i)
#define ALL(x) x.begin(),x.end()
#define ll long long
typedef pair<int,int> P;
const int inf=1000000007;
const int MOD=1000000007;
signed main(){
  int n;cin>>n;
  int res=0;
  rep1(i,n){
    if(i%3==0||i%5==0)continue;
    res+=i;
  }
  cout<<res<<"\n";
  return 0;
}
