#![allow(unused_imports, unused_macros)] use kyoproio::*; use std::{ collections::*, io::{self, prelude::*}, iter, mem::{replace, swap}, }; fn main() -> io::Result<()> { let f = || { let stdin = io::stdin(); let stdout = io::stdout(); solve(KInput::new(stdin.lock()), io::BufWriter::new(stdout.lock())) }; f(); return Ok(()); std::thread::Builder::new() .stack_size(64 * 1024 * 1024) .spawn(|| { let stdin = io::stdin(); let stdout = io::stdout(); solve(KInput::new(stdin.lock()), io::BufWriter::new(stdout.lock())) })? .join() .unwrap(); Ok(()) } fn solve(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(); } } } let (n, m): (usize, usize) = kin.input(); if m > n { outputln!("0"); return; } let tot = totient_table(n / m); // eprintln!("{:?}", &tot); let mut ans = 0; const MOD: i64 = 1e9 as i64 + 7; for i in 1..=n / m { ans += 2 * tot[i] as i64; } ans = (ans % MOD).saturating_sub(2) * fact(n as i64 - 2, MOD) % MOD; outputln!("{}", ans); } pub fn totient_table(n: usize) -> Vec { let mut t: Vec = (0..=n).collect(); for i in 2..=n { if t[i] == i { for j in (i..=n).step_by(i) { t[j] -= t[j] / i; } } } t } fn fact(n: i64, p: i64) -> i64 { let mut f = 1; for i in 2..=n { f *= i; if f > p { f %= p; } } f } // ----------------------------------------------------------------------------- pub mod kyoproio { use std::io::prelude::*; pub trait Input { fn str(&mut self) -> &str; 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: String, pos: usize, } impl KInput { pub fn new(src: R) -> Self { Self { src, buf: String::with_capacity(1024), pos: 0, } } pub fn src(&mut self) -> &mut R { &mut self.src } } impl Input for KInput { fn str(&mut self) -> &str { loop { if self.pos >= self.buf.len() { self.pos = 0; self.buf.clear(); if self.src.read_line(&mut self.buf).expect("io error") == 0 { return &self.buf; } } let range = self.pos ..self.buf[self.pos..] .find(|c: char| c.is_ascii_whitespace()) .map(|i| i + self.pos) .unwrap_or_else(|| self.buf.len()); self.pos = range.end + 1; if range.end > range.start { return &self.buf[range]; } } } } 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.str().as_bytes().to_owned() } } macro_rules! from_str_impl { { $($T:ty)* } => { $(impl InputParse for $T { fn input(src: &mut I) -> Self { src.str().parse::<$T>().expect("parse error") } })* } } from_str_impl! { String char bool f32 f64 isize i8 i16 i32 i64 i128 usize u8 u16 u32 u64 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_export] macro_rules! kdbg { ($($v:expr),*) => { if cfg!(debug_assertions) { dbg!($($v),*) } else { ($($v),*) } } } }