var y,x,r:longint; q,z,p:int64; Begin ReadLn(r); z:=0; y:=0; x:=r; q:=Sqr(r); Repeat p:=q-Sqr(y); While (Sqr(x)>=p) and (x>=0) do Dec(x); Inc(z,x+1); y:=y+1; Until y>r; z:=z*4; WriteLn(z); End.