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

import javax.crypto.CipherInputStream;
import javax.print.attribute.standard.PrinterLocation;
public class Main {
    public static void main (String [] argc)
    {
        BigInteger a[]=new BigInteger[210];
        int i,n;
        a[1]=BigInteger.valueOf(1);
        a[2]=BigInteger.valueOf(2);
        Scanner cin = new Scanner(System.in);
        for (i=3;i<=200;i++)
            a[i]=a[i-1].add(a[i-2]);
        while (cin.hasNext()) {
            n=cin.nextInt();
            System.out.println(a[n].toString());
        }
        
    }
}