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 Rust (1.42.0) (judge verdict: Wrong Answer)

use std::io;

fn main(){
    let stdin = io::stdin();
    let res = {
	let mut buf = String::new();
	stdin.read_line(&mut buf).unwrap();
	buf.retain(|c| c != '\n');
	
	let mut temp = buf.split_ascii_whitespace();
	temp.next().unwrap().parse::<u64>().unwrap() * ((temp.next().unwrap().parse::<f64>().unwrap() * 100.)   as u64) / 100
    };

    println!("{}",res);
}