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 proconio::input;

fn main() {
    input! {
        a: u128,
        b: String,
    }

    if let [s, t] = *b.split('.').collect::<Vec<_>>() {
        let s = s.parse::<u128>().unwrap();
        let t = t.parse::<u128>().unwrap();
        let ans = a * (100 * s + t) / 100;
        println!("{}", ans);
    } else {
        unreachable!();
    }
}