#![allow(non_snake_case)] #![allow(dead_code)] #![allow(unused_macros)] #![allow(unused_imports)] use std::str::FromStr; use std::io::*; use std::collections::*; use std::cmp::*; struct Scanner> { iter: std::iter::Peekable, } macro_rules! exit { () => {{ exit!(0) }}; ($code:expr) => {{ if cfg!(local) { writeln!(std::io::stderr(), "===== Terminated =====") .expect("failed printing to stderr"); } std::process::exit($code); }} } impl> Scanner { pub fn new(iter: I) -> Scanner { Scanner { iter: iter.peekable(), } } pub fn safe_get_token(&mut self) -> Option { let token = self.iter .by_ref() .skip_while(|c| c.is_whitespace()) .take_while(|c| !c.is_whitespace()) .collect::(); if token.is_empty() { None } else { Some(token) } } pub fn token(&mut self) -> String { self.safe_get_token().unwrap_or_else(|| exit!()) } pub fn get(&mut self) -> T { self.token().parse::().unwrap_or_else(|_| exit!()) } pub fn vec(&mut self, len: usize) -> Vec { (0..len).map(|_| self.get()).collect() } pub fn mat(&mut self, row: usize, col: usize) -> Vec> { (0..row).map(|_| self.vec(col)).collect() } pub fn char(&mut self) -> char { self.iter.next().unwrap_or_else(|| exit!()) } pub fn chars(&mut self) -> Vec { self.get::().chars().collect() } pub fn mat_chars(&mut self, row: usize) -> Vec> { (0..row).map(|_| self.chars()).collect() } pub fn line(&mut self) -> String { if self.peek().is_some() { self.iter .by_ref() .take_while(|&c| !(c == '\n' || c == '\r')) .collect::() } else { exit!(); } } pub fn peek(&mut self) -> Option<&char> { self.iter.peek() } } fn main() { let cin = stdin(); let cin = cin.lock(); let mut sc = Scanner::new(cin.bytes().map(|c| c.unwrap() as char)); let N: usize = sc.get(); let X: i64 = sc.get(); let A: Vec = sc.vec(N); let mut s = HashMap::new(); let mut ans = 0i64; for i in 0..N { if let Some(&c) = s.get(&A[i]) { ans += c; } *s.entry(X^A[i]).or_insert(0) += 1; } println!("{}", ans); }