den_1

#include<iostream>
#include<cmath>
#include<map>
#include<string>

using namespace std;

int  fib(int n){
  if(n == 0){
      return 0;
  }
  if(n == 1){
    return 1;
  }
  return fib(n-2) + fib(n-1);
}

int main() {

    cout << "enter n" << endl;
    int n;
    cin >> n;

    int i;
    for(i = 0; fib(i) <= n; i++);

    cout << fib(i) << endl;

}