/*
ID: 1292871202
LANG: C++
*/
#pragma comment(linker,"/STACK:102400000,102400000")
#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#include <iomanip>
#include <cmath>
#include <algorithm>
#include <stack>
#include <queue>
#include <map>
#include <fstream>
#include <utility>

using namespace std;

typedef long long ll;

const int INF = 0x3f3f3f3f;
const int MAX = 0x7fffffff;
const ll LINF = 0x3f3f3f3f3f3f3f3fLL;
const ll LMAX = 0x7fffffffffffffffLL;
const double eps = 1e-9;
const double pi=acos(-1.0);

const int maxn = 100000+5;
const int maxm = 100000+5;
const int mod = 1e9+7;

#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1

struct BigInt
{
    const static int mod = 10000;
    const static int DLEN = 4;
    int a[600],len;
    BigInt()
    {
        memset(a,0,sizeof(a));
        len = 1;
    }
    BigInt(int v)
    {
        memset(a,0,sizeof(a));
        len = 0;
        do
        {
            a[len++] = v%mod;
            v /= mod;
        }
        while(v);
    }
    BigInt(const char s[])
    {
        memset(a,0,sizeof(a));
        int L = strlen(s);
        len = L/DLEN;
        if(L%DLEN)len++;
        int index = 0;
        for(int i = L-1; i >= 0; i -= DLEN)
        {
            int t = 0;
            int k = i - DLEN + 1;
            if(k < 0)k = 0;
            for(int j = k; j <= i; j++)
                t = t*10 + s[j] - '0';
            a[index++] = t;
        }
    }
    BigInt operator +(const BigInt &b)const
    {
        BigInt res;
        res.len = max(len,b.len);
        for(int i = 0; i <= res.len; i++)
            res.a[i] = 0;
        for(int i = 0; i < res.len; i++)
        {
            res.a[i] += ((i < len)?a[i]:0)+((i < b.len)?b.a[i]:0);
            res.a[i+1] += res.a[i]/mod;
            res.a[i] %= mod;
        }
        if(res.a[res.len] > 0)res.len++;
        return res;
    }
    void output()
    {
        printf("%d",a[len-1]);
        for(int i = len-2; i >=0 ; i--)
            printf("%04d",a[i]);
        printf("\n");
    }
};

BigInt ans[2005];

void init()
{
    ans[1]=BigInt(1);
    ans[2]=BigInt(2);
    for(int i=3; i<=2000; ++i)
    {
        ans[i]=ans[i-1]+ans[i-2];
    }
}
int main()
{
    //freopen("input.txt","r",stdin);
    //freopen("output.txt","w",stdout);
    //cin.sync_with_stdio(false);
    //cout.sync_with_stdio(false);
    init();
    int n;
    while(cin>>n)
    {
        if(n==0)
        {
            printf("\n");
            continue;
        }
        ans[n].output();
    }
    return 0;
}