#include <stdio.h>
#include <math.h>

int main(){
  long double y;
  int x;
  scanf("%d %Lf", &x, &y);
  (long double) y=y*x;
  // printf("%llf\n", y);
  // printf("%llf\n", y);
  printf("%Lf\n", truncl((long double)y));
}