#include <stdio.h>


int main(void){
  int a = -1;
  double b = -1.0;
  
  scanf("%d %lf\n", &a, &b);

  // a = a_1 * 100 + a_2
  int a_1 = a / 100;
  int a_2 = a % 100;
  
  int result = a_1 * ((int)(b * 100)) + ((int)(a_2 * b));
  
  printf("%d\n", result);
  
  return 0;
}