#![allow(unused_imports, unused_macros, unknown_lints)] use std::collections::*; use std::cmp::Ordering::*; macro_rules! dump {($($e:expr), +) => {print!(concat!($(stringify!($e), " = {:?}\n"), +), $($e), +)}} macro_rules! max {($e0:expr, $($e:expr), +) => {{let mut r = $e0; $(r = std::cmp::max(r, $e);)+ r}}} macro_rules! min {($e0:expr, $($e:expr), +) => {{let mut r = $e0; $(r = std::cmp::min(r, $e);)+ r}}} fn main() { let mut n = get::val::(); let mut cs = (1usize..n+1).map(|x|x*(x+1)/2).take_while(|&x|x<=n).collect::>(); let mut ans = 0; while n > 0 { let m = cs[cs.len()-1]; if m > n { let _ = cs.pop(); continue } else { n -= m; ans += 1; } } println!("{}", ans) } #[allow(dead_code)] mod get { use std::io::*; use std::str::*; use std::process::*; pub fn val() -> T { let mut buf = String::new(); let s = stdin(); s.lock().read_line(&mut buf).ok(); if buf.is_empty() {println!("No input"); exit(0)} buf.trim_right().parse::().ok().unwrap() } pub fn vals(n: usize) -> Vec { let mut vec: Vec = vec![]; for _ in 0 .. n { vec.push(val()); } vec } pub fn tuple() -> (T1, T2) { let mut buf = String::new(); let s = stdin(); s.lock().read_line(&mut buf).ok(); if buf.is_empty() {println!("No input"); exit(0)} let mut it = buf.trim_right().split_whitespace(); let x = it.next().unwrap().parse::().ok().unwrap(); let y = it.next().unwrap().parse::().ok().unwrap(); (x, y) } pub fn tuples(n: usize) -> Vec<(T1, T2)> { let mut vec: Vec<(T1, T2)> = vec![]; for _ in 0 .. n { vec.push(tuple()); } vec } pub fn tuple3() -> (T1, T2, T3) { let mut buf = String::new(); let s = stdin(); s.lock().read_line(&mut buf).ok(); if buf.is_empty() {println!("No input"); exit(0)} let mut it = buf.trim_right().split_whitespace(); let x = it.next().unwrap().parse::().ok().unwrap(); let y = it.next().unwrap().parse::().ok().unwrap(); let z = it.next().unwrap().parse::().ok().unwrap(); (x, y, z) } pub fn tuple3s(n: usize) -> Vec<(T1, T2, T3)> { let mut vec: Vec<(T1, T2, T3)> = vec![]; for _ in 0 .. n { vec.push(tuple3()); } vec } pub fn vec() -> Vec { let mut buf = String::new(); let s = stdin(); s.lock().read_line(&mut buf).ok(); if buf.is_empty() {println!("No input"); exit(0)} buf.trim_right().split_whitespace().map(|t| t.parse::().ok().unwrap()).collect() } pub fn mat(h: usize) -> Vec> { let mut mat = vec![]; for _ in 0 .. h { mat.push(vec()); } mat } pub fn chars() -> Vec { let mut buf = String::new(); let s = stdin(); s.lock().read_line(&mut buf).ok(); if buf.is_empty() {println!("No input"); exit(0)} buf.trim_right().chars().collect() } } #[allow(dead_code)] mod put { use std::string::*; pub fn vec(vec: &Vec, sep: &str) { let out = vec.iter().map(|e| e.to_string()).collect::>().as_slice().join(sep); println!("{}", out); } pub fn mat(mat: &Vec>, sep: &str) { for v in mat { vec(v, sep); } } }