program MATCHES;

{$APPTYPE CONSOLE}

var n,a,s,d:integer;
begin
//assign(input,'matches.dat');reset(input);
//assign(output,'matches.sol');rewrite(output);
readln(n);
a:=trunc(sqrt(n));
d:=n-sqr(a);
s:=2*(a*(a+1)+d);
if d>0 then
begin
inc(s);
if d>a then inc(s)
end;
writeln(s);
//close(input);close(output)
end.