import java.io.*;
import java.math.*;
import java.util.*;
import java.text.*;

public class Main
{
    public static void main(String[] args)   {
        
        BigInteger a[] = new BigInteger[220];
        a[1] = BigInteger.valueOf(1);
        a[2] = BigInteger.valueOf(2);
        for(int i = 3; i < 203; i ++)
            a[i] = a[i-1].add(a[i-2]);
        
        Scanner cin = new Scanner (new BufferedInputStream(System.in));
        while(cin.hasNext())
        {
            int n = cin.nextInt();
            if(n == 0)
                 System.out.println("");
else
            System.out.println(a[n]);
        }
    }
}