#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i,n) for(int i=0;i<n;i++)
static const ll mod=1000000007;
#define int long long

signed main(void) {
  string v;
  int t;
  cin>>v>>t;
  int temp=0;
  rep(i,4){
    temp*=10;
    temp+=(v[i+2]-'0');
  } 
  cout<<(temp*t)/10000<<endl;
  return 0;
}