题解 | #不死神兔问题#

#include <iostream>
using namespace std;

int getSum(int n);

int main() {

    int n;
    cin >> n;

    cout << getSum(n) << endl;

    return 0;
}

int getSum(int n) {
     return (n==1||n==2)?1:getSum(n-1)+getSum(n-2);
    

}