#include<bits/stdc++.h>

using namespace std;

typedef long long ll;

void solve(){
    int n;
    cin >> n;
    ll s = 0;
    for(int i=1; i<=n; i++){
        if(i%3==0||i%5==0)
            continue;
        s += i;
    }
    cout << s;
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    ll t = 1, i = 1;
    //cin >> t;
    while(t--){
        solve();
        ++i;
    }
    return 0;
}
