#include <iostream>
#include <vector>

template<class T>
int binary_search(std::vector<T> items, const T& what) {
    return -1;
}

int main() {
    std::vector<int> items {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
    int index = binary_search(items, 2);
    std::cout<<index<<std::endl;
}