Problem:
Score : 300 points

Problem Statement

Compute A \times B, truncate its fractional part, and print the result as an integer.

Constraints

0 \leq A \leq 10^{15}

0 \leq B < 10

A is an integer.

B is a number with two digits after the decimal point.

Input

Input is given from Standard Input in the following format:

A B

Output

Print the answer as an integer.

Sample Input 1

198 1.10

Sample Output 1

217

We have 198 \times 1.10 = 217.8. After truncating the fractional part, we have the answer: 217.

Sample Input 2

1 0.01

Sample Output 2

0

Sample Input 3

1000000000000000 9.99

Sample Output 3

9990000000000000

Solution in Perl (5.26.1) (judge verdict: Wrong Answer)

my $s = <> ;chomp $s;
my ($A,$B) = split(/\s+/, $s);
my $ans;
my $mod;

if($A > 1000){
  $mod = substr($A,-2);
  $mod = int($mod * $B);  
  #print "$mod\n"; 
  my $AA = substr($A,0,-2);
#print "AA$AA\n";
  $B= int($B*100);
  $ans = $AA * $B;
  $ans = $ans + $mod;
}else{
  $ans = int ((($A * ($B*100) )-(($A * ($B*100))%100)) /100); 
}
print "$ans";