def create_S():
    current = []
    num = 1
    length = 0
    while length < 190:
        s = str(num)
        remaining = 190 - length
        if len(s) <= remaining:
            current.append(s)
            length += len(s)
        else:
            current.append(s[:remaining])
            length = 190
        num += 1
    return ''.join(current)

def multiply_str_num(s, n):
    if n == 0:
        return '0'
    reversed_s = s[::-1]
    result = []
    carry = 0
    for ch in reversed_s:
        digit = int(ch)
        product = digit * n + carry
        carry = product // 10
        result.append(product % 10)
    if carry != 0:
        result.append(carry)
    # Convert to string and remove leading zeros
    result_str = ''.join(map(str, reversed(result))).lstrip('0')
    return result_str if result_str else '0'

S = create_S()
N = int(input())
product_str = multiply_str_num(S, N)
L = len(product_str)

if L > 190:
    integer_part = product_str[:-190]
    fractional_part = product_str[-190:]
else:
    integer_part = '0'
    fractional_part = product_str.zfill(190)

print(f"{integer_part}.{fractional_part}")