#![allow(unused_imports, unused_macros)] use kyoproio::*; use std::{ collections::*, io::{self, prelude::*}, iter, mem::{replace, swap}, }; fn run(mut kin: I, mut out: O) { macro_rules! output { ($($args:expr),+) => { write!(&mut out, $($args),+).unwrap(); }; } macro_rules! outputln { ($($args:expr),+) => { output!($($args),+); outputln!(); }; () => { output!("\n"); if cfg!(debug_assertions) { out.flush().unwrap(); } } } // a ^ b == x // a ^ (b ^ x) == 0 let (n, x): (usize, u32) = kin.input(); let mut map = HashMap::new(); let mut ans = 0; for a in kin.iter::().take(n) { if let Some(&c) = map.get(&(a ^ x)) { ans += c as u64; } *map.entry(a).or_insert(0u32) += 1; } outputln!("{}", ans); } // ----------------------------------------------------------------------------- fn main() -> io::Result<()> { std::thread::Builder::new() .stack_size(64 * 1024 * 1024) .spawn(|| { run( KInput::new(io::stdin().lock()), io::BufWriter::new(io::stdout().lock()), ) })? .join() .unwrap(); Ok(()) } // ----------------------------------------------------------------------------- pub mod kyoproio { use std::io::prelude::*; pub trait Input { fn bytes(&mut self) -> &[u8]; fn str(&mut self) -> &str { std::str::from_utf8(self.bytes()).unwrap() } fn input(&mut self) -> T { T::input(self) } fn iter(&mut self) -> Iter { Iter(self, std::marker::PhantomData) } fn seq>(&mut self, n: usize) -> B { self.iter().take(n).collect() } } pub struct KInput { src: R, buf: Vec, pos: usize, len: usize, } impl KInput { pub fn new(src: R) -> Self { Self { src, buf: vec![0; 1 << 16], pos: 0, len: 0, } } } impl Input for KInput { fn bytes(&mut self) -> &[u8] { loop { while let Some(delim) = self.buf[self.pos..self.len] .iter() .position(|b| matches!(*b, b'\n' | b'\r' | b' ')) { let range = self.pos..self.pos + delim; self.pos += delim + 1; if delim > 0 { return &self.buf[range]; } } if self.pos > 0 { self.buf.copy_within(self.pos..self.len, 0); self.len -= self.pos; self.pos = 0; } if self.len >= self.buf.len() { self.buf.resize(2 * self.buf.len(), 0); } let read = self.src.read(&mut self.buf[self.len..]).unwrap(); if read == 0 { let range = self.pos..self.len; self.pos = self.len; return &self.buf[range]; } self.len += read; } } } pub struct Iter<'a, T, I: ?Sized>(&'a mut I, std::marker::PhantomData<*const T>); impl<'a, T: InputParse, I: Input + ?Sized> Iterator for Iter<'a, T, I> { type Item = T; fn next(&mut self) -> Option { Some(self.0.input()) } } pub trait InputParse: Sized { fn input(src: &mut I) -> Self; } impl InputParse for Vec { fn input(src: &mut I) -> Self { src.bytes().to_owned() } } macro_rules! from_str_impl { { $($T:ty)* } => { $(impl InputParse for $T { fn input(src: &mut I) -> Self { src.str().parse::<$T>().unwrap() } })* } } from_str_impl! { String char bool f32 f64 } macro_rules! parse_int_impl { { $($I:ty: $U:ty)* } => { $(impl InputParse for $I { fn input(src: &mut I) -> Self { let f = |s: &[u8]| s.iter().fold(0, |x, b| 10 * x + (b & 0xf) as $I); let s = src.bytes(); if let Some((&b'-', t)) = s.split_first() { -f(t) } else { f(s) } } } impl InputParse for $U { fn input(src: &mut I) -> Self { src.bytes().iter().fold(0, |x, b| 10 * x + (b & 0xf) as $U) } })* }; } parse_int_impl! { isize:usize i8:u8 i16:u16 i32:u32 i64:u64 i128:u128 } macro_rules! tuple_impl { ($H:ident $($T:ident)*) => { impl<$H: InputParse, $($T: InputParse),*> InputParse for ($H, $($T),*) { fn input(src: &mut I) -> Self { ($H::input(src), $($T::input(src)),*) } } tuple_impl!($($T)*); }; () => {} } tuple_impl!(A B C D E F G); macro_rules! array_impl { { $($N:literal)* } => { $(impl InputParse for [T; $N] { fn input(src: &mut I) -> Self { let mut arr = std::mem::MaybeUninit::uninit(); unsafe { let ptr = arr.as_mut_ptr() as *mut T; for i in 0..$N { ptr.add(i).write(src.input()); } arr.assume_init() } } })* }; } array_impl! { 1 2 3 4 5 6 7 8 } #[macro_export] macro_rules! kdbg { ($($v:expr),*) => { if cfg!(debug_assertions) { dbg!($($v),*) } else { ($($v),*) } } } }