Bài 1

#include <iostream>
using namespace std;

int Fibonance(const int& n){
    if(n < 1){
        return 0;
    }

    if(n == 1){
        return 1;
    }

    return Fibonance(n - 1) + Fibonance(n - 2);
}

int main(){
    int n;

    cout << "#input: ";
    cin >> n;

    cout << "#output: " << Fibonance(n) << endl;

    return 0;
}