#include<iostream>

using namespace std;

 int main()
{
   int n, c, i = 0, p = 1, w;
 int a[1000];
   for ( c = 0 ; c < 50; c++ )
   {
      if ( c <= 1 )
         w = c;
      else
      {
         w = i + p;
         i = p;
         p = w;
      }
      a[c]=w;
   }

   int o;
   cin>>o;
   for(int x=o;x<50;x++)
   {
	   cout<<a[x];
	   break;
   }

   system("pause");
}