#define _USE_MATH_DEFINES
#include <algorithm>
#include <cstdio>
#include <functional>
#include <iostream>
#include <cfloat>
#include <climits>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
using namespace std;

typedef long long ll;

int MOD = 1000000007;

int main() {
	string s; cin >> s;
	s = s.substr(2);
	stringstream ss(s);
	int v; ss >> v;
	int t; cin >> t;
	cout << v * t / 10000 << endl;
}