{$APPTYPE CONSOLE}
var i,n,m,k,s:longint;f:text;
begin
assign(f,'Matches.dat');reset(f);
readln(f,n);close(f);s:=0;
m:=trunc(sqrt(n));k:=n-sqr(m);s:=s+(2*(m*(m+1)));
if k>0 then
for i:=1 to k do
if (i=1) or (i=m+1) then s:=s+3 else s:=s+2;
assign(f,'Matches.sol');rewrite(f);
write(f,s);close(f);
end.