#include <iostream> #include <cstdio> #include <cmath> #include <cstdio> #include <cstring> #include <string> #include <vector> #include <set> #include <map> #include <stack> #include <queue> #include <deque> #include <algorithm> #define CK(N,A,B) (A<=N&&N<B) #define REP(i,a,b) for(int i=a;i<b;i++) #define RREP(i,a,b) for(int i=(b-1);a<=i;i--) #define F first #define S second #define ll long long const int INF = 1e9; const long long LLINF = 1e15; using namespace std; int main(){ ll v,t; scanf("0.%lld %lld", &v, &t); cout<<v*t/10000LL<<endl; return 0; }