#pragma GCC optimize ("O3")

#include <bits/stdc++.h>
#define DEBUG true
#ifdef ONLINE_JUDGE
#undef DEBUG
#define DEBUG false
#endif 

using namespace std;

#define TRACE(args...) { string _s = #args; replace(_s.begin(), _s.end(), ',', ' '); stringstream _ss(_s); istream_iterator<string> _it(_ss); err(_it, args); cerr << endl;}

void err(istream_iterator<string> it) {}
template<typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
	cerr << "[" << *it << " = " << a << "]";
	err(++it, args...);
}

#define MAXN ((int)2e5+5)
#define MOD ((int)1e9 + 7)
#define INF ((int)1e9 + 9)
#define ll long long
#define _ << " " <<
#define CLEAR(a, b) memset(a, b, sizeof(a))
#define LOG(x) if(DEBUG) cerr << x << endl;
#define pb push_back
#define all(x) x.begin(), x.end()
#define endl "\n"
#define pii pair<int,int>
#define mid ((l+r)/2)

int main()
{
	ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
	ll ans = 0;
	ll a;
	double b, f;
	cin >> a >> b;
	ll w = b*100 + 0.01;

	ans = (a*w) / 100;

	cout << fixed << ans << endl;
}

/* stuff you should look for
	* int overflow, array bounds
	* special cases (n=1?)
	* do smth instead of nothing and stay organized
	* WRITE STUFF DOWN
*/
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define mod 1000000007


int main()
{
    int t=1;
    //cin>>t;

    while( t-- )
    {
        int a,b;
        cin>>a>>b;
        cout<<a*b;
    }
    return 0;
}
