#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>  
#include <ext/pb_ds/tree_policy.hpp>   
using namespace std;
using namespace __gnu_pbds;  
typedef tree<int, null_type, less<int>, rb_tree_tag,  tree_order_statistics_node_update>  ordered_set; 
#define num1 1000000007
#define num2 998244353
#define REP(i,a,n) for(ll i=a;i<n;i++)
#define REPd(i,a,n) for(ll i=a; i>=n; i--)
#define vll vector<long long>
#define pll pair<long long, long long>
#define vpll vector< pair<long long, long long>>
#define pb push_back
#define pob pop_back
#define f first
#define s second
#define fix(f,n) std::fixed<<std::setprecision(n)<<f
#define all(x) x.begin(), x.end()
#define M_PI 3.14159265358979323846
#define epsilon (double)(0.00000000001)
#define mm 1000000000000000000ll
#define watch(x) cerr << (#x) << " is " << (x) << endl 
typedef long long ll;

// DEBUG FUNCTIONS FOR TEST 
#ifndef ONLINE_JUDGE

#define error(args...) { string _s = #args; replace(_s.begin(), _s.end(), ',', ' '); stringstream _ss(_s); istream_iterator<string> _it(_ss); err(_it, args); }

void err(istream_iterator<string> it) {}
template<typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
	cerr << *it << " = " << a << endl;
	err(++it, args...);
}

template<typename T>
void __p(T a) {
  cout<<a;
}
template<typename T, typename F>
void __p(pair<T, F> a) {
  cout<<"{";
  __p(a.first);
  cout<<",";
  __p(a.second);
  cout<<"}";
}
template<typename T>
void __p(std::vector<T> a) {
  cout<<"{";
  for(auto it=a.begin(); it<a.end(); it++)
    __p(*it),cout<<",}"[it+1==a.end()];
}
template<typename T, typename ...Arg>
void __p(T a1, Arg ...a) {
  __p(a1);
  __p(a...);
}
template<typename Arg1>
void __f(const char *name, Arg1 &&arg1) {
  cout<<name<<" : ";
  __p(arg1);
  cout<<endl;
}
template<typename Arg1, typename ... Args>
void __f(const char *names, Arg1 &&arg1, Args &&... args) {
  int bracket=0,i=0;
  for(;; i++)
    if(names[i]==','&&bracket==0)
      break;
    else if(names[i]=='(')
      bracket++;
    else if(names[i]==')')
      bracket--;
  const char *comma=names+i;
  cout.write(names,comma-names)<<" : ";
  __p(arg1);
  cout<<" | ";
  __f(comma+1,args...);
}
#define trace(...) cout<<"Line:"<<__LINE__<<" ", __f(#__VA_ARGS__, __VA_ARGS__)
#else
#define trace(...)
#define error(...)
#define endl '\n'
#endif

// DEBUG FUNCTIONS END 
 
ll mod_exp(ll a, ll b, ll c)
{
	ll res=1;
	a=a%c;
	while(b>0)
	{
		if(b%2==1)
		{
			res=(res*a)%c;
		}
		b/=2;
		a=(a*a)%c;
	}
	return res;
}
ll mymod(ll a,ll b)
{
    return ((a%b)+b)%b;
}
// bool prime[200001];
// void SieveOfEratosthenes() 
// { 
//     memset(prime, true, sizeof(prime)); 
//     prime[1]=false;
//     for (int p=2; p*p<=200000; p++) 
//     { 
//         if (prime[p] == true) 
//         { 
//             for (int i=p*p; i<=200000; i += p) 
//                 prime[i] = false; 
//         } 
//     } 
//     return;
// }
// ll powe[200005];
// void power()
// {
//     powe[0]=1;
//     REP(i,1,200005)
//     {
//         powe[i]=mymod(2*powe[i-1],num);
//     }
// }
// ll gcdExtended(ll,ll,ll *,ll *);
// ll modInverse(ll a, ll m) 
// { 
//     ll x, y; 
//     ll g = gcdExtended(a, m, &x, &y); 
//         ll res = (x%m + m) % m;
//         return res;
// } 
// ll gcdExtended(ll a, ll b, ll *x, ll *y) 
// { 
//     if (a == 0) 
//     { 
//         *x = 0, *y = 1; 
//         return b; 
//     } 
//     ll x1, y1; 
//     ll gcd = gcdExtended(b%a, a, &x1, &y1); 
//     *x = y1 - (b/a) * x1; 
//     *y = x1; 
//     return gcd; 
// }
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    ll a;
	long double b;
	cin>>a>>b;
	cout << (ll)((long double)(a) * b) <<"\n";
    return 0;
}


Measured memory_bytes: 3744