fn main() { input!(n: usize, m: usize); let mut pow = vec![M::zero(); 41]; for i in 2..pow.len() { pow[i] = M::from(i).pow(n as u64); } let (s, l) = prime_count(m); let small = s .iter() .map(|s| M::from(*s) * pow[2]) .collect::>(); let large = l .iter() .map(|s| M::from(*s) * pow[2]) .collect::>(); let mut prime = vec![]; let sq = small.len() - 1; enumerate_prime(sq, |p| prime.push(p)); let ans = recurse(|rec, (v, val, mut po): (usize, M, usize)| -> M { let mut ans = val; while po < prime.len() && (v * prime[po]).saturating_mul(prime[po]) <= m { let mut v = v * prime[po]; let mut c = 1; while v <= m { ans += rec((v, val * pow[c + 1], po + 1)); v *= prime[po]; c += 1; } po += 1; } let (pi, sp) = if v <= sq { (l[v], large[v]) } else { (s[n / v], small[n / v]) }; if po < pi { ans += val * sp; if po > 0 { ans -= val * small[prime[po - 1]]; } } ans })((1, M::one(), 0)); println!("{}", ans); } // ---------- begin input macro ---------- // reference: https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8 #[macro_export] macro_rules! input { (source = $s:expr, $($r:tt)*) => { let mut iter = $s.split_whitespace(); input_inner!{iter, $($r)*} }; ($($r:tt)*) => { let s = { use std::io::Read; let mut s = String::new(); std::io::stdin().read_to_string(&mut s).unwrap(); s }; let mut iter = s.split_whitespace(); input_inner!{iter, $($r)*} }; } #[macro_export] macro_rules! input_inner { ($iter:expr) => {}; ($iter:expr, ) => {}; ($iter:expr, $var:ident : $t:tt $($r:tt)*) => { let $var = read_value!($iter, $t); input_inner!{$iter $($r)*} }; } #[macro_export] macro_rules! read_value { ($iter:expr, ( $($t:tt),* )) => { ( $(read_value!($iter, $t)),* ) }; ($iter:expr, [ $t:tt ; $len:expr ]) => { (0..$len).map(|_| read_value!($iter, $t)).collect::>() }; ($iter:expr, chars) => { read_value!($iter, String).chars().collect::>() }; ($iter:expr, bytes) => { read_value!($iter, String).bytes().collect::>() }; ($iter:expr, usize1) => { read_value!($iter, usize) - 1 }; ($iter:expr, $t:ty) => { $iter.next().unwrap().parse::<$t>().expect("Parse error") }; } // ---------- end input macro ---------- // ---------- begin prime count ---------- // pi(i): i以下の素数の数 // small[i]: pi(i) // large[i]: pi(floor(n / i)) // として、 (small, large) を返す // O(N^(3/4)) pub fn prime_count(n: usize) -> (Vec, Vec) { let sqrt = (1..).find(|p| p * p > n).unwrap() - 1; let mut large = vec![0; sqrt + 1]; let mut small = vec![0; sqrt + 1]; for (i, (large, small)) in large.iter_mut().zip(&mut small).enumerate().skip(1) { *large = n / i - 1; *small = i - 1; } fn mydiv(a: usize, b: u32) -> u32 { (a as f64 / b as f64) as u32 } for p in 2..=sqrt { if small[p] == small[p - 1] { continue; } let pi = small[p] - 1; let q = p * p; let d = sqrt / p; for i in 1..=d { large[i] -= large[i * p] - pi; } let m = n / p; let r = sqrt.min(n / q); for i in (d + 1)..=r { large[i] -= small[mydiv(m, i as u32) as usize] - pi; } for i in (p..=d).rev() { let sub = small[i] - pi; small[(i * p)..].iter_mut().take(p).for_each(|p| *p -= sub); } } (small, large) } // ---------- end prime count ---------- // ---------- begin modint ---------- use std::marker::*; use std::ops::*; pub trait Modulo { fn modulo() -> u32; } pub struct ConstantModulo; impl Modulo for ConstantModulo<{ M }> { fn modulo() -> u32 { M } } pub struct ModInt(u32, PhantomData); impl Clone for ModInt { fn clone(&self) -> Self { Self::new_unchecked(self.0) } } impl Copy for ModInt {} impl Add for ModInt { type Output = ModInt; fn add(self, rhs: Self) -> Self::Output { let mut v = self.0 + rhs.0; if v >= T::modulo() { v -= T::modulo(); } Self::new_unchecked(v) } } impl AddAssign for ModInt { fn add_assign(&mut self, rhs: Self) { *self = *self + rhs; } } impl Sub for ModInt { type Output = ModInt; fn sub(self, rhs: Self) -> Self::Output { let mut v = self.0 - rhs.0; if self.0 < rhs.0 { v += T::modulo(); } Self::new_unchecked(v) } } impl SubAssign for ModInt { fn sub_assign(&mut self, rhs: Self) { *self = *self - rhs; } } impl Mul for ModInt { type Output = ModInt; fn mul(self, rhs: Self) -> Self::Output { let v = self.0 as u64 * rhs.0 as u64 % T::modulo() as u64; Self::new_unchecked(v as u32) } } impl MulAssign for ModInt { fn mul_assign(&mut self, rhs: Self) { *self = *self * rhs; } } impl Neg for ModInt { type Output = ModInt; fn neg(self) -> Self::Output { if self.is_zero() { Self::zero() } else { Self::new_unchecked(T::modulo() - self.0) } } } impl std::fmt::Display for ModInt { fn fmt<'a>(&self, f: &mut std::fmt::Formatter<'a>) -> std::fmt::Result { write!(f, "{}", self.0) } } impl std::fmt::Debug for ModInt { fn fmt<'a>(&self, f: &mut std::fmt::Formatter<'a>) -> std::fmt::Result { write!(f, "{}", self.0) } } impl Default for ModInt { fn default() -> Self { Self::zero() } } impl std::str::FromStr for ModInt { type Err = std::num::ParseIntError; fn from_str(s: &str) -> Result { let val = s.parse::()?; Ok(ModInt::new(val)) } } impl From for ModInt { fn from(val: usize) -> ModInt { ModInt::new_unchecked((val % T::modulo() as usize) as u32) } } impl From for ModInt { fn from(val: u64) -> ModInt { ModInt::new_unchecked((val % T::modulo() as u64) as u32) } } impl From for ModInt { fn from(val: i64) -> ModInt { let mut v = ((val % T::modulo() as i64) + T::modulo() as i64) as u32; if v >= T::modulo() { v -= T::modulo(); } ModInt::new_unchecked(v) } } impl ModInt { pub fn new_unchecked(n: u32) -> Self { ModInt(n, PhantomData) } pub fn zero() -> Self { ModInt::new_unchecked(0) } pub fn one() -> Self { ModInt::new_unchecked(1) } pub fn is_zero(&self) -> bool { self.0 == 0 } } impl ModInt { pub fn new(d: u32) -> Self { ModInt::new_unchecked(d % T::modulo()) } pub fn pow(&self, mut n: u64) -> Self { let mut t = Self::one(); let mut s = *self; while n > 0 { if n & 1 == 1 { t *= s; } s *= s; n >>= 1; } t } pub fn inv(&self) -> Self { assert!(!self.is_zero()); self.pow(T::modulo() as u64 - 2) } pub fn fact(n: usize) -> Self { (1..=n).fold(Self::one(), |s, a| s * Self::from(a)) } pub fn perm(n: usize, k: usize) -> Self { if k > n { return Self::zero(); } ((n - k + 1)..=n).fold(Self::one(), |s, a| s * Self::from(a)) } pub fn binom(n: usize, k: usize) -> Self { if k > n { return Self::zero(); } let k = k.min(n - k); let mut nu = Self::one(); let mut de = Self::one(); for i in 0..k { nu *= Self::from(n - i); de *= Self::from(i + 1); } nu * de.inv() } } // ---------- end modint ---------- // ---------- begin precalc ---------- pub struct Precalc { fact: Vec>, ifact: Vec>, inv: Vec>, } impl Precalc { pub fn new(n: usize) -> Precalc { let mut inv = vec![ModInt::one(); n + 1]; let mut fact = vec![ModInt::one(); n + 1]; let mut ifact = vec![ModInt::one(); n + 1]; for i in 2..=n { fact[i] = fact[i - 1] * ModInt::new_unchecked(i as u32); } ifact[n] = fact[n].inv(); if n > 0 { inv[n] = ifact[n] * fact[n - 1]; } for i in (1..n).rev() { ifact[i] = ifact[i + 1] * ModInt::new_unchecked((i + 1) as u32); inv[i] = ifact[i] * fact[i - 1]; } Precalc { fact, ifact, inv } } pub fn inv(&self, n: usize) -> ModInt { assert!(n > 0); self.inv[n] } pub fn fact(&self, n: usize) -> ModInt { self.fact[n] } pub fn ifact(&self, n: usize) -> ModInt { self.ifact[n] } pub fn perm(&self, n: usize, k: usize) -> ModInt { if k > n { return ModInt::zero(); } self.fact[n] * self.ifact[n - k] } pub fn binom(&self, n: usize, k: usize) -> ModInt { if k > n { return ModInt::zero(); } self.fact[n] * self.ifact[k] * self.ifact[n - k] } } // ---------- end precalc ---------- type M = ModInt>; // ---------- begin enumerate prime ---------- pub fn enumerate_prime(n: usize, mut f: F) where F: FnMut(usize), { assert!(1 <= n && n <= 5 * 10usize.pow(8)); let batch = (n as f64).sqrt().ceil() as usize; let mut is_prime = vec![true; batch + 1]; for i in (2..).take_while(|p| p * p <= batch) { if is_prime[i] { let mut j = i * i; while let Some(p) = is_prime.get_mut(j) { *p = false; j += i; } } } let mut prime = vec![]; for (i, p) in is_prime.iter().enumerate().skip(2) { if *p && i <= n { f(i); prime.push(i); } } let mut l = batch + 1; while l <= n { let r = std::cmp::min(l + batch, n + 1); is_prime.clear(); is_prime.resize(r - l, true); for &p in prime.iter() { let mut j = (l + p - 1) / p * p - l; while let Some(is_prime) = is_prime.get_mut(j) { *is_prime = false; j += p; } } for (i, _) in is_prime.iter().enumerate().filter(|p| *p.1) { f(i + l); } l += batch; } } // ---------- end enumerate prime ---------- // ---------- begin recurse ---------- // reference // https://twitter.com/noshi91/status/1393952665566994434 // https://twitter.com/shino16_cp/status/1393933468082397190 pub fn recurse(f: F) -> impl Fn(A) -> R where F: Fn(&dyn Fn(A) -> R, A) -> R, { fn call(f: &F, a: A) -> R where F: Fn(&dyn Fn(A) -> R, A) -> R, { f(&|a| call(f, a), a) } move |a| call(&f, a) } // ---------- end recurse ----------