x=int(input())

def zeta(x):
    Z=0
    for i in range(2,10000000):
        Z+=i**(-x)
        if i**(-x)<10**(-17):
            break
    return Z
if x==3:
    print(355065)
else:
    ANS=0.35506603315200247
    for i in range(3,x):
        ANS-=zeta(i)

    print(int(ANS*(10**6)))