#include <bits/stdc++.h>
using namespace std;
 
int main(){
    long long a;
    double b;
    cin >> a >> b;
    int B = b * 100;
    long long c = a * B / 100;
    cout << c << endl;
}
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll inf = 1e9+7;

int main(){

    ll a,b;
    cin>>a>>b;
    cout << a*b;

}

