别抄哦

#include <bits/stdc++.h>
using namespace std;
int main(){
int n,a[60];
cin >> n;
a[1] = 1,a[2] = 1,a[3] = 2;
for(int i = 4;i <= 50;i++){
a[i] = a[i-1] + a[i-3];
}
cout << a[n];
return 0;
}