What is the result of the following code?

function performOperation(x, operation) {
  function sum(y) {
    return x + y;
  }
  function subtract(y) {
    return x - y;
  }
  if (operation === "sum") {
    return sum;
  }
  return subtract;
}
const addFive = performOperation(5, "sum");
console.log(addFive(3));