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 JavaScript (Node.js 12.16.1) (judge verdict: Wrong Answer)

process.stdin.resume();
process.stdin.setEncoding('utf8');

let inputData = '';
let a, b;

process.stdin.on('data', inputStdin => {
  inputData += inputStdin;
});

process.stdin.on('end', _ => {
  inputData = inputData.replace(/\s*$/g, '')
    .split(' ');
  main();
});

function solve() {
  return a * b / 100n;
}

function main() {
  a = BigInt(inputData[0]);
  b = BigInt(Math.floor(inputData[1] * 100));

  process.stdout.write(solve().toString());
}