#![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::<i64>(); for i in 3.. { let sum = i * (i + 1) / 2; if sum > n { break; } if (n - sum) % i == 0 { println!("YES"); return; } } println!("NO"); } fn read<T: std::str::FromStr>() -> T { let mut s = String::new(); std::io::stdin().read_line(&mut s).ok(); s.trim().parse().ok().unwrap() } fn read_vec<T: std::str::FromStr>() -> Vec<T> { read::<String>() .split_whitespace() .map(|e| e.parse().ok().unwrap()) .collect() }