#include<vector> 
#include<iostream>
using namespace std;
int n;
//long long array[201];
string array[201];
void add(int k)
{
    string a = array[k - 1];
    string b = array[k - 2];
    //array[i].
    //array[]
    array[k].resize(50);
    vector<char> v;
    int lena = a.size();
    int lenb = b.size();
    int i = lena - 1, j = lenb - 1;
    int t;
    int jw = 0;
    while(i >= 0 && j >= 0)
    {
        t = a[i] - '0' + b[j] - '0' + jw;
        v.push_back(t % 10 + '0');
        jw = t / 10;
        i--;
        j--;
    } 
    while(i >= 0){
        t = a[i] - '0' + jw;
        v.push_back(t % 10 + '0');
        jw = t /10;
        i--;
    }
    while(j >= 0){
        t = b[j] - '0' + jw;
        v.push_back(t % 10 + '0');
        jw = t / 10;
        j--;
    }
    while(jw > 0){
        v.push_back(jw % 10 + '0');
        jw /= 10;
    }
    char ch[50];
    for(i=0; i<v.size(); i++){
        ch[i] = v[v.size() - i - 1];
        
    }
    ch[i] = '\0';
    //array[k][i] = '\0';
    array[k] = ch;
    
}
int main()
{
    int i;
    array[1] = "1";
    array[2] = "2";
    while(cin >> n)
    {
        if(array[n] == "")
        {
            for(i=3; i<=n; i++)
            {
                //array[i] = array[i - 1] + array[i - 2];
                add(i);
            }
        }
//        for(i=0; i<50; i++)
//        {
//            if(array[n][i] != '\0')
//            cout << array[n][i];
//        }
//        cout << endl;
        cout << array[n] << endl;
    }
    return 0;
}