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 <bits/stdc++.h>
#include <iostream>
#include <vector>
#include <cstdlib>
#include <cmath>
#include <math.h>
#define rep(i, n) for(int i = 0; i < n; i++)
using namespace std;
using ll=long long;
using vll = vector<ll>;
using vvll = vector<vector<ll>>;

int main() {
	int64_t a; cin>>a;
	long double b;cin>>b;
	long double B=b*100;
	long double x=(a*B)/100;
	cout<<fixed<<setprecision(0)<<x<<endl;
}