fn main() {
    let mut n = String::new();
    std::io::stdin().read_line(&mut n).ok();
    let n: u64 = n.trim().parse().unwrap();

    let mut answer = 0;
    for n_try in 0..=(n / 5) {
        for n_conversion in 0..=n_try {
            let sum = 5 * n_try + 2 * n_conversion;
            if sum > n {
                break;
            }
            if (n - sum) % 3 == 0 {
                answer += 1;
            }
        }
    }

    println!("{answer}");
}