task16

function f( n : integer) : integer;
begin
  if n <= 1 then result := 0;
  if (n>1) and (n mod 2 = 0) then result := n div 2 + f(n-1) + 2;
  if (n>1) and (n mod 2 = 1) then result := f(n-1) + 3*n*n;
end;


begin
  print(f(49));
end.