function main(input) {
    // const list = input.split(" ").map(v => Number(v));
    // const a = list[0];
    // const b = list[1];

    const strNumbers = input.split(" ");
    const a = strNumbers[0].replace('\.', '') + "00";
    const b = strNumbers[1].replace('\.', '') + "00";

    const result = Math.floor(a * b/100/100);
    console.log(result);
}


// let input = "198 1.10";
// let input = "1 0.01";
// let input = "1000000000000000 9.99";
// main(input);
main(require("fs").readFileSync("/dev/stdin","utf8"));
  