#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
#define N 225
int n,m,k,l,t,s;
struct node{
    int l,a[N];
}f[N];
int c[N];
void add(node a,node b,int n){
    int l=max(a.l,b.l);
    for (int i=1;i<=l;i++)f[n].a[i]=a.a[i]+b.a[i];
    for (int i=1;i<=l;i++){
        f[n].a[i+1]+=f[n].a[i]/10;
        f[n].a[i]%=10;
    }
    if(f[n].a[l+1])l++;
    f[n].l=l;
}
int main(){
    f[1].l=1;f[2].l=1;
    f[1].a[1]=1;f[2].a[1]=2;
    for (int i=3;i<=200;i++)add(f[i-1],f[i-2],i);
    while(scanf("%d",&n)!=EOF){
        for (int i=f[n].l;i;i--)printf("%d",f[n].a[i]);
        printf("\n");
    }
}