fn gcd(a: usize, b: usize) -> usize { let r = a % b; if r > 0 { gcd(b, r) } else { b } } fn main() { let [a, b]: [usize; 2] = { let mut buf = String::new(); std::io::stdin().read_line(&mut buf).unwrap(); let mut iter = buf.split_whitespace(); [ iter.next().unwrap().parse().unwrap(), iter.next().unwrap().parse().unwrap(), ] }; let c = gcd(a, b); let d = (c as f64).sqrt() as usize; if c == (d - 1) * (d - 1) || c == d * d || c == (d + 1) * (d + 1) { println!("Odd"); } else { println!("Even"); } }