#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i,m,n) for(int i=m; i<n; ++i)
#define repl(i,m,n) for(ll i=m; i<n; ++i)

int main(){
    string v; int t;
    cin >> v >> t;

    int vv = stoi(v.substr(2,4));
    int ans = vv * t;

    cout << ans / 10000 << endl;
    return 0;
}