#![allow(unused_imports)]
use std::cmp::*;
use std::collections::*;
use std::io::Write;
use std::ops::Bound::*;

#[allow(unused_macros)]
macro_rules! debug {
    ($($e:expr),*) => {
        #[cfg(debug_assertions)]
        $({
            let (e, mut err) = (stringify!($e), std::io::stderr());
            writeln!(err, "{} = {:?}", e, $e).unwrap()
        })*
    };
}

fn main() {
    let v = read_vec::<i64>();
    let (a, b) = (v[0], v[1]);
    if a == 0 && b == 0 {
        println!("0.25");
        return;
    }
    if a == 0 || b == 0 {
        let mut ans = 0.0;
        for bi in -20..20 {
            let x = (2i64 + bi * b + bi * a) as f64;
            if x >= 20.0 || 2i64 + bi * b + bi * a < 0 {
                continue;
            }
            ans += 1. / x.powf(x);
        }
        println!("{}", ans);
        return;
    }
    if a == b {
        let mut ans = 0.0;
        for ai in 0..20 {
            let x = (2i64 + 2 * ai * a) as f64;
            if x >= 20.0 || 2i64 + 2 * ai * a < 0 {
                continue;
            }
            ans += 1. / x.powf(x);
        }
        println!("{}", ans);
        return;
    }
    let mut ans = -0.25;
    for _ in 0..2 {
        for ai in -20..20 {
            for bi in -20..20 {
                let x = (2i64 + ai * a + bi * b) as f64;
                if x >= 20.0 || 1 + ai * a < 0 || 1 + bi * b < 0 {
                    continue;
                }
                ans += 1. / x.powf(x);
            }
        }
    }
    println!("{}", ans);
}

fn read<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}

fn read_vec<T: std::str::FromStr>() -> Vec<T> {
    read::<String>()
        .split_whitespace()
        .map(|e| e.parse().ok().unwrap())
        .collect()
}