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#include <iostream>
#include <string_view>
#include <vector>
#include <algorithm>

enum class in_danger_t : uint8_t { none = 0, one = 1, both = 2};

struct area_t
{
	uint32_t size;
	in_danger_t danger;
	
	area_t()
		: size(0)
		, danger(in_danger_t::none)
	{
	}

	void reduce_size(uint32_t v)
	{
		while (v > 0)
		{
			if (size > 0)
			{
				--size;
			}
			else
			{
				return;
			}
			--v;
		}
	}
 	
	void pass(bool & vaccin)
	{
		if (danger == in_danger_t::none)
		{
			return;
		}
		else if (danger == in_danger_t::one)
		{
			if (vaccin)
			{
				danger = in_danger_t::none;
				vaccin = false;
			}
			else
			{
				reduce_size(1);
			}
			
		}
		else 
		{
			if (vaccin)
			{
				danger = in_danger_t::one;
				vaccin = false;
				reduce_size(1);
			}
			else
			{
				reduce_size(2);
			}
		}
	}
	
	bool update(char prev, char c)
	{
		if (c == '0')
		{
			++size;
			if (prev == '1')
			{
				danger = in_danger_t::one;
				size = 1;
			}
			if (prev == ' ')
			{
				size = 1;
			}
		}
		else if (c == '1')
		{
			if (prev == '0')
			{
				danger = 
					danger == in_danger_t::none ?
					in_danger_t::one :
					in_danger_t::both;
				return true;
			}
		}
		return false;
	}

	friend std::ostream& operator<<(std::ostream& out, area_t area)
	{
		if (area.danger == in_danger_t::none)
		{
			out << "["<< area.size << "]";
		}
		else if (area.danger == in_danger_t::one)
		{
			out << "1["<< area.size << "]";

		}
		else if (area.danger == in_danger_t::both)
		{
			out << "1["<< area.size << "]1";
		}
		return out;
	}
	
	bool operator>(area_t const& a2) const
	{
		if (size > a2.size)
		{
			return true;
		}
		else if (size == a2.size)
		{
			if (danger == in_danger_t::one)
			{
				return true;
			}
			else if (danger == in_danger_t::both &&
				a2.danger == in_danger_t::none)
			{
				return true;
			}
			else 
			{
				return false;
			}
		}
		return false;
	}

	bool is_vaccinable()
	{
		return danger != in_danger_t::none && size >0;;
	}
};

struct test_case_t
{
	uint32_t size;
	std::vector<area_t> areas;
	bool steady;
	test_case_t()
		: size(0)
		, areas()
		, steady(false)
	{}

	friend std::ostream& operator<<(std::ostream& out, test_case_t& tc)
	{
		out << tc.size << "\n";
		for (auto const & a : tc.areas)
		{
			out << a << "\n";
		}
		return out;
	}
	
	friend std::istream& operator>>(std::istream& in, test_case_t& tc)
	{
		in >> tc.size;
		area_t area{};
		char prev = ' ';
		char c;
		for (uint32_t i = 0; i < tc.size; ++i)
		{
			in >> c;
			if (area.update(prev, c))
			{
				tc.areas.emplace_back(area);
			}

			prev = c;
		}
		if (c == '0')
		{
			tc.areas.emplace_back(area);
		}
		std::sort(tc.areas.begin(), tc.areas.end(),
				[](area_t const& a1, area_t const& a2) {return a1 > a2;});
		return in;
	}
	
	uint32_t single_pass()
	{
		bool vaccin = true;
		uint32_t result = 0;
		bool vaccinable = false;
		for (auto &e : areas)
		{
			e.pass(vaccin);
			vaccinable |= e.is_vaccinable();
			result += e.size;
		}
		if (vaccinable == false)
		{
			steady = true;
		}
		else
		{
			std::sort(areas.begin(), areas.end(),
				[](area_t const& a1, area_t const& a2) {return a1 > a2;});
		}
		return result;
	}
};


uint32_t solution(std::istream& input, std::ostream& out)
{
	uint32_t num_cases = 0;
	input >> num_cases;
	for (uint32_t i = 0; i < num_cases; ++i)
	{
		test_case_t tc;
		input >> tc;
	//	out << tc;
		uint32_t result = 0;
		do
		{
			result = tc.single_pass();
	//		out << tc;
		}
		while(!tc.steady);
		out << (tc.size - result) << "\n";

	}
	
	uint32_t result = 0;
	return result;
}

#ifndef TEST
int main(int argc, char* argv[])
{
	solution(std::cin, std::cout);
	return 0;
}
#endif