#include <cxxopts.hpp>
#include <fmt/format.h>
#include <range/v3/view.hpp>

namespace view = ranges::views;

int fib(int x) {
  int a = 0, b = 1;

  for (int it : view::repeat(0) | view::take(x)) {
    (void)it;
    int tmp = a;
    a += b;
    b = tmp;
  }

  return a;
}