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