import java.math.BigInteger;
import java.util.Scanner;

public class Main {
    private static BigInteger a[] = new BigInteger[210];
    public static void init(){
        a[1] = BigInteger.ONE;
        a[2] = a[1].add(BigInteger.ONE);
        for(int i = 3; i <= 200; i++){
            a[i] = a[i-1].add(a[i-2]);
        }
    }
    public static void main(String[] args) {
        init();
        Scanner in = new Scanner(System.in);
        int tmp;
        while(in.hasNext()){
            tmp = in.nextInt();
            System.out.println(a[tmp]);
        }
    }

}