#include <boost/bind.hpp>
#include <vector>
#include <iostream>
 
using namespace std;
 
void f2(vector<int> &h)
{
        h.clear();
        h.push_back(0);
}
 
void f1(vector<int> &h)
{
        boost::bind(f2, boost::ref(h));
}
 
int main()
{
        vector<int> h;
        f1(h);
 
        cout << h.size() << "\n";
}