use std::io::{read_to_string, stdin}; fn get_primes(to: u64) -> Vec { let mut primes = vec![2]; for i in (3..=to).step_by(2) { if i * i > to { break; } for p in primes.iter() { if i % p == 0 { break; } if p * p > i { primes.push(i); break; } } } primes } fn prime_factorization(mut n: u64, primes: &Vec) -> Vec { let mut factors = vec![]; for p in primes { while n % p == 0 { factors.push(*p); n /= p; } if n == 1 { break; } } if n != 1 { factors.push(n); } factors } fn get_mathematical_least_common_parent(a: u64, b: u64) -> u64 { let primes = get_primes(a.max(b)); let mut a_factors = prime_factorization(a, &primes); let mut b_factors = prime_factorization(b, &primes); a_factors.reverse(); b_factors.reverse(); let mut res = 1; for (p1, p2) in a_factors.iter().zip(b_factors.iter()) { if p1 == p2 { res *= p1; } else { break; } } res } fn main() { let line = read_to_string(stdin()).unwrap(); let mut iter = line.trim().split(' ').map(|x| x.parse::().unwrap()); let (a, b) = (iter.next().unwrap(), iter.next().unwrap()); println!("{}", get_mathematical_least_common_parent(a, b)); }