#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<algorithm>
using namespace std;
struct Bigint{
    int len;
    int s[1010];
    Bigint(){}
    Bigint(int x)
    {
        len=0;
        while (x)
        {
            s[++len]=x % 10;
            x/=10;
        }
    }
    void init()
    {
        memset(s,0,sizeof(s));
    }
    void print()
    {
        for (int i=len;i>=1;--i)putchar(s[i]+'0');
        puts("");
    }
}Fib[210],t;
int n;
Bigint add(Bigint &a,Bigint &b)
{
    t.init();
    t.len=max(a.len,b.len);
    for (int i=1;i<=t.len;++i) t.s[i]=a.s[i]+b.s[i];
    for (int i=1;i<=t.len;++i) t.s[i+1]+=t.s[i]/10,t.s[i]%=10;
    while (t.s[t.len+1]!=0) t.len++;
    return t;
}
int main()
{
    Fib[1]=Bigint(1);Fib[2]=Bigint(2);
    for (int i=3;i<=200;++i) Fib[i]=add(Fib[i-1],Fib[i-2]);
    while(scanf("%d",&n)!=EOF) Fib[n].print();
    return 0;
}