#include<iostream>
#include<vector>
#include<string>


using ll = long long;


int main(){
    int n;
    std::cin >> n;
    ll sum = 0;
    for(int i = 1; i <= n; i++){
        if(i % 3 != 0 && i % 5 != 0){
            sum += i;
        }
    }
    std::cout << sum << std::endl;
    return 0;
}
