program Matches;
var f,fr:text;
    n,k,a:integer;
begin
assign(f,'Matches.dat');
assign(fr,'Matches.sol');
reset(f);
readln(f,n);
close(f);
a:=trunc(sqrt(n));
n:=n-(a*a);
k:=(a*(a+1))*2;
k:=k+(n*2);
if n<>0 then
 begin
   if a<n then k:=k+2 else k:=k+1;
 end;
 rewrite(fr);
 writeln(fr,k);
 close(fr);
end.