https://programmers.co.kr/learn/courses/30/lessons/12900#
#include <string>
#include <vector>
using namespace std;
int solution(int n) {
int pivo[60001];
pivo[1] = 1;
pivo[2] = 2;
for(int i=3;i<=n;i++){
pivo[i] = (pivo[i-2]+pivo[i-1])%1000000007;
}
return pivo[n]%1000000007;
}