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: Accepted)

use std::io::Read;

fn input() -> (i64,f64) {
    let mut buf = String::new();
    std::io::stdin().read_to_string(&mut buf).unwrap();
    let mut iter = buf.split_whitespace();
    
    let a:i64 = iter.next().unwrap().parse().unwrap();
    let b:f64 = iter.next().unwrap().parse().unwrap();
    (a,b)
}

fn main() {
    let (a,b) = input();
    let b = (b*100.0+0.001) as i64;
    let res = a*b/100;
    println!("{}",res);
}