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 <iostream>
#include <iomanip>
typedef long long ll;
using namespace std;
const  ll INF = 1e9;
const  ll MOD = 1e9 + 7;
#define repi(i,n,init) for(ll i=init;i<(n);i++)

int main()
{
    ll a;
    double b;
    cin >> a >> b;
    cout << a * ll(b * 100) / 100 << endl;
    return 0;
}