#include<iostream>
#include<vector>
#include<algorithm>

using namespace std;

int main(){
    int N;
    cin >> N;

    long long ans(0);

    for(int i=1;i<=N;++i){
        if(i%3 == 0 or i%5 == 0) continue;
        ans += i;
    }

    cout << ans << endl;
    
    return 0;
}
