#include <vector>
#include <iostream>
#include <algorithm>
#include <functional>
#include <string>
#include <math.h>
#include <map>
#include <iomanip>
using namespace std;

int main(){
	double v,t;
	cin >> v >> t;
	v*=10000;
	int ans=v*t;
	if(ans%10000>=5000)ans++;
	ans/=10000;
	cout << ans << endl;
	return 0;
}