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 (Clang 10.0.0) (judge verdict: Wrong Answer)

#include <stdio.h>

int main()
{

    long long  a;
    double b;

    scanf("%lld", &a);
    scanf("%lf", &b);
    double c =( b * 100.0);
    int z = c / 100;//1のくらいのみ
   // printf("1けため%d\n",z);
    int q = ((int)c - z*100) / 10;
    int r = ((int)c - z * 100-q*10);
  //  printf("2けため%d\n",q);
    //printf("2けため%d\n", r);

    printf("%lld", a * (long long)z + a * (long long)(q) / 10l + a * (long long)(r) / 100l);

    printf("\n");
}