#include <iostream>
#include <string>

using namespace std;

int fib(int x) {
    if (x == 1 || x == 0) {
        return 1;
    }
    return fib(x-1)+fib(x-2);
}

int main() {

    int num;
    while(cin >> num){
        cout << fib(num) << endl;
    }


}