-module('Main').
-export([main/1]).

main(_) ->
    {ok, [A, B]} = io:fread("", "~d ~s"),
    [BeforeDot, AfterDot|_] = string:split(B, "."),
    {BeforeDotInt, _} = string:to_integer(BeforeDot),
    {AfterDotInt, _} = string:to_integer(AfterDot),
    B100 = BeforeDotInt * 100 + AfterDotInt,
    Ans = A * B100 div 100,
    io:format("~p~n", [Ans]),
    halt().