f

#include <iostream>
using namespace std;
int main()
{
    int n = 0, f = 0, i = 0, k1 = 1, k2 = 1;
    cin >> n;
   if (n > 2){
    while (i != n)
    {
      f = k1 + k2;
      k1 = k2;
      k2 = f;
      i++;
    }
    cout << f;
   }
   if (n == 0)
    {
        cout << n;
    }
      if ((n == 1) || (n == 2))
    {
        cout << n;
    }
    return 0;
}