import * as fs from "fs";
import "core-js";

const main = (input) => {
  const args = input.trim().split(" ");
  const first = BigInt(parseInt(args[0], 10));
  const second = BigInt(args[1].replace(".", ""));
  const answer = (first * second).toString();

  console.log(answer.length > 2 ? answer.slice(0, -2) : 0);
};

main(fs.readFileSync("/dev/stdin", "utf8"));