include [HTML_REMOVED]

include [HTML_REMOVED]

include [HTML_REMOVED]

using namespace std;

int f(int n)
{
if(n == 1) return 1;
if(n == 2) return 2;
return f(n-1) + f(n-2);
}

int main()
{
int n;
cin >> n;

count << f(n) << end1;

return 0;

}