import std;

auto input()
{
    return readln().chomp();
}

alias sread = () => readln.chomp();
alias aryread(T = long) = () => readln.split.to!(T[]);

void main()
{
    real a, b;
    scan(a, b);
    writefln("%d", floor(a * b).to!long);

}

void scan(L...)(ref L A)
{
    auto l = readln.split;
    foreach (i, T; L)
    {
        A[i] = l[i].to!T;
    }
}
