https://programmers.co.kr/learn/courses/30/lessons/12900
function solution(n) {
let answer = 0;
let dp = Array(n+1).fill(0);
dp[1] = 1;
dp[2] = 2;
for(let i = 3; i <=n ; i++){
dp[i] = (dp[i-2] + dp[i-1])% 1000000007;
}
return dp[n]
}