import numpy as np
eps = 1e-6

n = int(input())
p = float(input())
q = float(input())
if abs(p - 1) < eps:
    print(1.0)
    exit()

A = np.eye(n * 2, dtype=np.float64)
X = np.arange(1, n * 2)
Y = np.arange(1, n * 2)
Y[X % 2 == 0] += 1
Y[X % 2 == 1] -= 1
np.add.at(A, (X, Y), -p)

X = np.arange(1, n * 2 - 1)
Z = np.arange(1, n * 2 - 1)
Z[X % 2 == 0] -= 2
Z[X % 2 == 1] += 2
np.add.at(A, (X, Z), -q)

b = np.zeros(2 * n, dtype=np.float64)
b[0] = 1.0

res = np.linalg.solve(A, b)
print(res[1])