#include <malloc.h>
#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

//ABC169D
//ABC169C
int main(void) {
  long long n, k, i, cou=0, tmp;
  double b;
  scanf("%lld %lf", &n, &b);
  k=b*100;
  printf("%lld", n*k/100);

}