import java.util.*;



import java.math.*;
public class Main{
    public static void main(String args[]){
        Scanner in = new Scanner(System.in);
        BigInteger [] arr = new BigInteger[222];
        arr[1] = BigInteger.ONE;
        arr[2] = BigInteger.valueOf(2);
        for(int i=3;i<=200;i++)
            arr[i] = arr[i-1].add(arr[i-2]);
        while(in.hasNext()){
            int a = in.nextInt();
            System.out.println(arr[a]);
        }
    }
}

//a+b*c+(d*e+f)*g