n = int(input())
t = n + 10
b = 10 ** t
x1 = b * 4 // 5
x2 = b // -239
s = x1 + x2
n *= 2
for i in range(3, n, 2):
    x1 //= -25
    x2 //= -57121
    x = (x1 + x2) // i
    s += x
pai = s * 4
pai //= 10000000000
pai = str(pai - 3 * (10 ** (n // 2)))
print(3, end='.')
for i in range(len(pai)):
    if (i % 50 == 0):
        print()
    elif (i % 10 == 0):
        print(end=' ')
    print(pai[i], end='')