#include <iostream>
#include <algorithm>
#include <vector>
#include <cstdio>
#include <cmath>

using namespace std;
typedef unsigned char byte;
typedef long long int LLint;
typedef unsigned long long int uLLint;

int main(){
    int v,t;
    char str[8];
    
    cin>>str>>t;
    v=stoi(str+2);
    
    printf("%d\n",v*t/10000);
    return 0;
}