#include <iostream>
using namespace std;
 
template <typename Fnc, typename Args>
void t (Fnc f, Args arg) {
  f (arg);
}
 
void foo (int x) {
  cout<<x;
}
void bar (int& x) {
  cout << ++x;
}
 
template <typename T>
struct refholder {
  T *ptr;
  refholder(T& x):ptr(&x){}
  operator T& () { return *ptr; }
};
 
template <typename T>
refholder<T> makeref (T& x) {
  return refholder<T>(x);
}
 
int main () {
  int x=2;
  t (foo, x);
  t (bar, makeref(x));
  cout << x;
}
 

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