#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
typedef long long ll;
int n,i;
struct Bignum
{
    int len,a[250];
    Bignum()
    {
        len=0;
        memset(a,0,sizeof a);
    }
    void print()
    {
        for (int i=len;i>=1;i--)printf("%d",a[i]);puts("");
    }
}num[250];
Bignum operator +(Bignum a,Bignum b)
{
    Bignum c;
    c.len=max(a.len,b.len)+1;
    int x=0,i;
    for (i=1;i<=c.len;i++)
    {
        c.a[i]=a.a[i]+b.a[i]+x;
        x=c.a[i]/10;
        c.a[i]=c.a[i]%10;
    }
    while (c.len>1&&c.a[c.len]==0)c.len--;
    return c;
}
int main()
{
    num[1].len=num[1].a[1]=num[2].len=1;num[2].a[1]=2;
    for (i=3;i<=205;i++) num[i]=num[i-1]+num[i-2];
    while (scanf("%d",&n)!=EOF)
        num[n].print();
}