I have question about initializing variables in namespace

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C++14

#include <iostream>

using namespace std;

namespace AAA
{
	namespace BBB
	{
		namespace CCC
		{
			int num1, num2;
		}
	}
}

int main()
{
	namespace ABC = AAA::BBB::CCC;
	cout << ABC::num1 << ABC::num2 << endl;
	return 0;
}

What I have tried:

As you see, I didn't initialize variable num1, num2 in namespace AAA::BBB::CCC. In the normal case, It is correct that num1 and num2 should have garbage values, but I have confirmed that both were 0 after compilation. Why?