import java.util.*;
import java.math.*;
import java.util.regex.*;
public class Main
{
    public static void main(String[] args)
    {
        Scanner cin = new Scanner(System.in);
        BigInteger[] a = new BigInteger[205];
        a[0] = BigInteger.valueOf(0);
        a[1] = BigInteger.valueOf(1);
        a[2] = BigInteger.valueOf(2);
        for(int i=3;i<=200;i++)
        {
          a[i]=a[i-1].add(a[i-2]);
        }
        while(cin.hasNext())
        {
          int t=cin.nextInt();
          System.out.println(a[t]);
        }
        cin.close();
    }
}