#include <iostream> #include <algorithm> #include <string> #include <vector> #include <map> #include <set> #include <stdio.h> #include <cstring> #include <queue> #include <stack> #include <functional> #include <math.h> #include <iomanip> using namespace std; #define Would #define you const int INF = 999999999; const int MOD = 1e9 + 7; const double pi = 3.141592653589793238; int main() { int a, b; scanf("0.%d%d", &a, &b); cout << a * b / 10000 << endl; }