function pair(a, b) {
  return function (selector) {
    if (selector) {
      return a;
    }
    return b;
  }
}

function first(p) {
  if (p) {
    return p(true);
  }
}

function remaining(p) {
  if (p) {
    return p(false);
  }
}

function enqueue(element, p) {
  return pair(element, p);
}

function get(nth, q) {
  if (nth === 0) {
    return first(q);
  }
  return get(nth - 1, remaining(q));
}

console.log(get(2, enqueue(3, enqueue(2, enqueue(1)))));