var A:Array[1..5001] of longint; i,j,k,d,n:longint; cv,S,max:real;
f:text;
Begin
assign(f,'TAMGIAC.INP'); reset(f);
readln(f,n);
for i:=1 to n do read(f,A[i]);
assign(f,'TAMGIAC.OUT'); rewrite(f);
d:=0;
for i:=1 to n-2 do
for j:=i+1 to n-1 do
for k:=j+1 to n do
if (A[i]+A[j]>A[k]) and (A[i]+A[k]>A[j]) and (A[j]+A[k]>A[i]) then
Begin
inc(d);
cv:=(A[i]+A[j]+A[k])/2;
S:=sqrt(cv(cv-A[i])(cv-A[j])*(cv-A[k]));
if S>max then max:=S;
end;
writeln(f,d);
close(f);
end.