N = int(input())
p1 = (1/6)**(N)
p2 = (1/3)**(N)-2*p1
p3 = (1/2)**(N)-3*p2-3*p1
p4 = (2/3)**(N)-4*p3-6*p2-4*p1
p5 = (5/6)**(N)-5*p4-10*p3-10*p2-5*p1
p6 = 1-6*p5-15*p4-20*p3-15*p2-6*p1
print(p6)