const result = file
  .split("\n")
  .map(Number)
  .reduce((acc, cur) => {
    let input = cur;
    let sum = 0;

    for (;;) {
      const r = Math.max(Math.floor(input / 3) - 2, 0);
      sum += r;
      input = r;
      if (input === 0) {
        break;
      }
    }

    return acc + sum;
  }, 0);