#include <iostream> 
using namespace std;

int main() {
    string v;
    int t;
    cin >> v >> t;
    cout << ((v[2] - '0') * 1000 + (v[3] - '0') * 100 + (v[4] - '0') * 10 + (v[5] - '0')) * t / 10000 << endl;
}