How to make [std::operator""s] visible in a namespace?

#include <chrono>

namespace X
{
using namespace std;
struct A
{
    std::chrono::seconds d = 0s; // ok
};
}

namespace Y
{
struct B
{
    std::chrono::seconds d = 0s; // error
};
}

The error message is:

error : no matching literal operator for call to 'operator""s' with argument of type 'unsigned long long' or 'const char *', and no matching literal operator template std::chrono::seconds d = 0s;

My question is:

I don't want to use namespace std; in namespace Y; then, how should I make std::operator""s visible in namespace Y?