#include <iostream>
using namespace std;

int Fibonacci(int n)
{
    if (n == 1 || n == 0)
        return 1;
    else
    {
        return Fibonacci(n - 1) + Fibonacci(n - 2);
    }
}

int main()
{
    int n;
    cin >> n;
    cout << Fibonacci(n) << endl;

    return 0;
}