#![allow(unused_imports)] use std::cmp::*; use std::collections::*; use std::io::Write; use std::ops::Bound::*; #[allow(unused_macros)] macro_rules! debug { ($($e:expr),*) => { #[cfg(debug_assertions)] $({ let (e, mut err) = (stringify!($e), std::io::stderr()); writeln!(err, "{} = {:?}", e, $e).unwrap() })* }; } fn main() { let n = read::(); let mut ans = 0; for p in 0.. { if p * 3 > n { break; } let n = n - p * 3; for t in 0.. { if t * 5 > n { break; } let res = n - 5 * t; if res % 2 == 0 && res / 2 <= t { ans += 1; } } } println!("{}", ans); } fn read() -> T { let mut s = String::new(); std::io::stdin().read_line(&mut s).ok(); s.trim().parse().ok().unwrap() } fn read_vec() -> Vec { read::() .split_whitespace() .map(|e| e.parse().ok().unwrap()) .collect() }