import java.lang.*;
import java.util.*;

public class Test1 {
	static int fib(int n) {
		if ( n == 0 ) return 0;
		if ( n == 1 ) return 1;
		return fib(n-2) + fib(n-1);
	}
	public static void main(String args[]) {
		int f = fib(28);
		Integer n = new Integer(f);
		System.out.println(n.toString());
	}
};