#include<iostream>
using namespace std;

int fib(int n) {
    if (n < 3) {
        return 1;
    }
    return fib(n - 1) + fib(n - 2);
}

int main() {
    int n = 0;
    while (cin >> n) {
        int sum = fib(n);
        cout << sum << endl;
    }
    return 0;
}