use std::io::*; use std::str::FromStr; #[allow(dead_code)] fn get_line() -> String { let stdin = stdin(); let mut line = String::new(); stdin.lock().read_line(&mut line).expect("io error."); line.trim().to_string() } #[allow(dead_code)] fn cast(s: &str) -> T { s.parse().ok().expect("parse error.") } #[allow(dead_code)] fn get_vec() -> Vec { (&get_line()).split(' ').map(cast::).collect() } fn main() { let v: Vec = get_vec(); let xv: Vec = get_vec(); println!("{}", if v[0] * v[1] == xv.iter().sum::() { "YES" } else { "NO" } ); }