#include <bits/stdc++.h>
using namespace std;
typedef long long LL;

int main() {
    string V,T;cin>>V>>T;
    V.erase(1,1);
    LL v=stoi(V),t=stoi(T);
    LL d=(v*t)/10000;
    cout<<d<<endl;
    return 0;
}