int a[35],b[35],c[35],d[35];
void jiaziji();
int main ()
{
    int n=0;
    cin>>n;
    for (int i=0;i<35;i++)
    {
        a[i]=0;
        b[i]=0;
        c[i]=0;
        d[i]=0;
    }
    a[34]=1;b[34]=1;
    for (int i=0;i<n;i++) jiaziji();
    if (n==0) cout<<'1'<<endl;
    else//????????????? 
    {
        int p=0;
        for (int i=0;i<35;i++)
        {
            if (c[i]!=0) 
            {
                p=i;
                break; 
            }
        }
        for (int i=p;i<35;i++)
        {
            cout<<c[i];
        }
    }
    
    return 0;
}

void jiaziji()//????????????????? 
{
     for (int i=34;i>0;i--)//c????????d???????a?b????????????? 
     { 
         c[i]=a[i]+b[i]+d[i];
         if (c[i]>9) //???? 
         {
              c[i]-=10;
              d[i-1]+=1;
         }
     }
     for (int i=0;i<35;i++)//????????????????????a?b???d???? 
     {
         a[i]=c[i];
         b[i]=c[i];
         d[i]=0;
     }
}
