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>
#include <stdlib.h>
#include <string.h>
#define MOD 1000000007
#define INF 1000000000000000000
#define PI 3.14159265359
#define ull unsigned long long
#define MYPOW_t int


int main(){
    ull a,B,hyaku,juu,iti,ans=0;
    float b;
    scanf("%lld%f",&a,&b);
    b*=100;
    B=(ull)b;
    hyaku=B/100;
    B-=hyaku*100;
    juu=B/10;
    B-=juu*10;
    iti=B;
    ans=hyaku*a+(juu*a)/10+(iti*a)/100;
    printf("%lld",ans);
    return 0;
}