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 C (GCC 9.2.1) (judge verdict: Wrong Answer)

#include<stdio.h>
int main(){
  long long a,b,x1,x2,x3,x4,d,e,f;
  double c;
  scanf("%lld %lf",&a,&c);
  b=c*100LL;
  d=b/100LL;
  e=(b/10LL)%10LL;
  f=b%10LL;
  //printf("%lld %lld %lld\n",d,e,f);
  x1=(a*d);
  x2=(a*e)/10LL;
  x3=(a*f)/100LL;
  x4=((a*e)%10*10)+(a*f)%100;
  
  //printf("%lld\n",b%100);
  //printf("%lld %lld %lld\n",x1,x2,x3);
  printf("%lld\n",x1+x2+x3+(x4/100));
  return 0;
}