a = -1.1
k = 1.4
tol = float(input())
nmax = int(input())
sum_1 = -0.40087
total = 0
error = 1
for i in range (1,nmax+1):
     total += ((a**i)*(2*i - 1))/(k**(2*i+1))
     error = i/total
     if abs(error)<=tol:
          break
     
print(total)