#include <iostream>
#include <type_traits>

using namespace std;

template <unsigned int x>
constexpr enable_if_t<x != 0U, int> log2 = 1 + log2<x / 2U>;

template <>
constexpr int log2<1U> = 0;

int main() {
  int foo[log2<8U>];
  
  cout << log2<8U> << endl;
}