编辑代码

// 设置标准输入接口
const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;

void (async function () {
  const n = Number(await readline());
  const dp = Array.from({ length: n }, () => 0);
  dp[0] = 1;
  dp[1] = 1;
  dp[2] = 2;
  for (let i = 3; i < n; i++) {
    dp[i] = dp[i - 1] + dp[i - 3];
  }
  console.log(dp[n - 1]);
})();