var a:array[1..800] of longint;
    b:array[1..60000] of longint;
    n:longint;
    
procedure init;
var f:text; i:longint;
begin
  assign(f,'nrtri.in');
  reset(f);
  read(f,n);
  for i:=1 to n do begin read(f,a[i]); {write(a[i],' ');}end; {writeln;}
  close(f);
end;

function tr(a,b,c:longint):boolean;
begin
  tr:=(a+b>=c)and(a+c>=b)and(b+c>=a);
end;

procedure calc;
var i,j,k,s:longint; f:Text;
begin
  s:=0;
  for i:=1 to n-2 do
    for j:=i+1 to n-1 do
      for k:=j+1 to n do
         if tr(a[i],a[j],a[k]) then s:=s+1;
  assign(f, 'nrtri.out');
  rewrite(f);
  write(f,s);
  close(f);
end;
    
begin
  init;
  calc;
end.