fn get_primes(max: usize) -> Vec<usize> {
    let mut is_prime = vec![true; max + 1];
    is_prime[0] = false;
    is_prime[1] = false;

    for n in 2..=max {
        if !is_prime[n] {
            continue;
        }
        if n * n > max {
            break;
        }
        for i in ((n * n)..=max).step_by(n) {
            is_prime[i] = false;
        }
    }

    (0..=max).filter(|&n| is_prime[n]).collect()
}

fn get_n_divisors(max: usize, primes: &[usize]) -> Vec<usize> {
    let mut n_divisors = vec![1; max + 1];

    for n in 2..=max {
        let mut n_tmp = n;
        for &p in primes {
            if p * p > n_tmp {
                break;
            }
            if n_tmp % p == 0 {
                let mut n_p = 1;
                while n_tmp % p == 0 {
                    n_tmp /= p;
                    n_p += 1;
                }
                n_divisors[n] *= n_p;
            }
        }
        if n_tmp > 1 {
            n_divisors[n] *= 2;
        }
    }

    n_divisors
}

fn main() {
    let mut xx = String::new();
    std::io::stdin().read_line(&mut xx).ok();
    let xx: Vec<&str> = xx.split_whitespace().collect();

    let n: usize = xx[0].parse().unwrap();
    let p: f64 = xx[1].parse().unwrap();
    let q = 1. - p;

    let primes = get_primes(n);
    let n_divisors = get_n_divisors(n, &primes);

    println!(
        "{}",
        (2..=n)
            .map(|i| q.powi(n_divisors[i] as i32 - 2))
            .sum::<f64>()
    );
}