function Main(input) {
  input = input.replace(/\n/g, ' ');
  input = input.split(" ");
  var A = Number(input[0]);
  var B = Number(input[1])*100;
  var c = "" + A*B;
  console.log(Math.floor(c.slice(0,c.length-2)));
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));