var n,i,nr,ls,ld,m,aux:longint;
f,g:text;
ok,g1:boolean;
v:array[1..801] of integer;
begin
assign(f,'nrtri.in');reset(f);
assign(g,'nrtri.out');rewrite(g);
read(f,n);
nr:=0;
for i:=1 to n do
read(f,v[i]);
repeat
ok:=false;
for i:=1 to n-1 do
   if v[i]>v[i+1] then begin
   ok:=true;
   aux:=v[i];
   v[i]:=v[i+1];
   v[i+1]:=aux;
   end;
   until ok;
{ls:=1;
ld:=n;
g1:=false;
while (ls<=ld) and (not g1) do begin
m:=(ls+ld) div 2;
if v[m]+v[m+1]>=v[m+2] then ls:=m+1
                       else ld:=m-1;
nr:=nr+1;
end;
writeln(g,nr-(n-2*(n div 2)));     }
for i:=1 to n-2 do begin
if v[i]+v[i+1]>v[i+2] then nr:=nr+1;
end;
writeln(g,nr);
close(f);
close(g);
end.