import java.util.Scanner;  
import java.math.BigInteger;  
public class Main {  
    public static BigInteger[]dp=new BigInteger[205];  
    public static void main(String[] args) {  
        // TODO Auto-generated method stub  
        Scanner cin=new Scanner(System.in);  
        //int n=cin.nextInt();  
        Init();  
        while(cin.hasNext())  
        {  
            int n=cin.nextInt();  
            if(n>=1&&n<=200)  
            {  
                System.out.print(dp[n]);  
            }  
            System.out.println();  
        }  
          
          
    }  
    public static void Init()  
    {  
        dp[1]=new BigInteger("1");  
        dp[2]=new BigInteger("2");  
        for(int i=3;i<=201;i++)  
        {  
            dp[i]=dp[i-1].add(dp[i-2]);  
        }  
    }  
  
}