#include <iostream> using namespace std; int main() { int k; cin >> k; if (k == 0) { cout << "0" << endl; return 0; } else if (k == 1) { cout << "1" << endl; return 0; } int a = 0, b = 1, fib = 0; for (int i = 2; i <= k; ++i) { fib = a + b; a = b; b = fib; } cout<< fib << endl; return 0; }