var
r,x,y,z:longint;
q,t:int64;
Begin
ReadLn(r);
q:=sqr(r);
For x:=0 to r do
Begin
t:=Sqr(x);
For y:=0 to r do
If t+Sqr(y)<q then Inc(z);
End;
WriteLn(4*z);
End.