Problem:
Score : 300 points

Problem Statement

Compute A \times B, truncate its fractional part, and print the result as an integer.

Constraints

0 \leq A \leq 10^{15}

0 \leq B < 10

A is an integer.

B is a number with two digits after the decimal point.

Input

Input is given from Standard Input in the following format:

A B

Output

Print the answer as an integer.

Sample Input 1

198 1.10

Sample Output 1

217

We have 198 \times 1.10 = 217.8. After truncating the fractional part, we have the answer: 217.

Sample Input 2

1 0.01

Sample Output 2

0

Sample Input 3

1000000000000000 9.99

Sample Output 3

9990000000000000

Solution in OCaml (4.10.0) (judge verdict: Accepted)

let (a, b) = Scanf.sscanf (read_line ()) "%d %s" @@ fun a b -> (a, b)
let b = int_of_string @@ Str.replace_first (Str.regexp "\\.") "" b

let () = Printf.printf "%d\n" @@ a * b / 100