program task1simple;
var n,i,j,k:integer;
  a: array[1..1000] of integer;
begin
  readln(N);
  for i := 1 to N do
    read(a[i]);
  for i := 1 to N-1 do
  begin
    for j:=i+1 to N do
    if ((a[i] +a[j])mod 2 <> 0) and ((a[i]*a[j]) mod 5 = 0) then k := k+1;
    end;
    write(k);
    end.