from decimal import *
n = int(input())
p = Decimal(input())
q = Decimal(input())
prob = [[Decimal(0) for i in range(n+2)] for j in range(3010)]
prob[0][1] = Decimal(1)
ret = Decimal(0)
for i in range(3000):
    for j in range(1, n+1):
        prob[i+1][j-1] += prob[i][j] * p
        prob[i+1][j+1] += prob[i][j] * q
    ret += prob[i][0]
print(ret)