const x = new Map();
  for (let i = 0; i < 100; i++) {
    x.set(`${i}${i}`, i);
  }

  for (let i = 0; i < 100; i++) {
    if (x.get(`${i}${i}`) + x.get(`${i}${i}`) !== i + i) {
      throw new Error('bad');
    }
  }

  const x = {};
  for (let i = 0; i < 100; i++) {
    x[`${i}${i}`] = i;
  }

  for (let i = 0; i < 100; i++) {
    if ((x[`${i}${i}`] + x[`${i}${i}`]) !== i + i) {
      throw new Error('bad');
    }
  }