#include <algorithm>
#include <array>
#include <cmath>
#include <cstdio>
#include <iostream>
#include <numeric>
#include <optional>
#include <queue>
#include <unordered_map>
#include <unordered_set>
#include <vector>

using namespace std;

int main() {
    string sv;
    int32_t t;
    cin >> sv >> t;
    int32_t v = stoi(sv.substr(2));
    auto ans = v * t;
    cout << ans / 10000 << endl;
    return 0;
}