class Fibonacci {
    static long fibonacci(long n) {
        if (n <= 1) {
            return n;
        }
        return fibonacci(n-1) + fibonacci(n-2);
    }
    public static void main(String[] args) {
        long arg = Integer.parseInt(args[0]);
        if (arg < 0) arg = 0;
        System.out.println("f(" + arg + ") = " + fibonacci(arg));
    }
}