#include <bits/stdc++.h>
using namespace std;
namespace JiKai_Thinks_ZiQi_Is_Delicious
{
	int T, n;
	string s1, s2, t1, t2;
	void main()
	{
		cin >> T;
		while (T--)
		{
			cin >> n >> s1 >> s2 >> t1 >> t2;
			s1 += '0'; s2 += '1'; t1 += '0'; t2 += '0';
			int c1[2] = {0, 0}, c2[2] = {0, 0}, ans = 0;
			for (int i = 0, j = 0; i <= n && j <= n;)
			{
				while (t1[i] != '0') s1[i] == '0' ? c1[0]++ : c1[1]++, i++;
				while (t2[j] != '0') s2[j] == '0' ? c2[0]++ : c2[1]++, j++;
				if (i == j) ans += min(c1[0], c2[0]) + min(c1[1], c2[1]) + (s1[i] == s2[j]), c1[0] = c1[1] = c2[0] = c2[1] = 0, i++, j++;
				else if (i < j) 
				{
					s1[i] == '0' ? c1[0]++ : c1[1]++; i++;
					if (c1[0] <= c2[0]) ans += c1[0], c2[0] -= c1[0], c1[0] = 0;
					else ans += c2[0], c2[1] -= c1[0] - c2[0], c1[0] = c2[0] = 0;
					if (c1[1] <= c2[1]) ans += c1[1], c2[1] -= c1[1], c1[1] = 0;
					else ans += c2[1], c2[0] -= c1[1] - c2[1], c1[1] = c2[1] = 0;
				}
				else
				{
					s2[j] == '0' ? c2[0]++ : c2[1]++; j++;
					if (c2[0] <= c1[0]) ans += c2[0], c1[0] -= c2[0], c2[0] = 0;
					else ans += c1[0], c1[1] -= c2[0] - c1[0], c2[0] = c1[0] = 0;
					if (c2[1] <= c1[1]) ans += c2[1], c1[1] -= c2[1], c2[1] = 0;
					else ans += c1[1], c1[0] -= c2[1] - c1[1], c2[1] = c1[1] = 0;
				}
			}
			cout << ans << "\n";
		}
	}
}
int main()
{
	freopen("edit.in", "r", stdin); freopen("edit.out", "w", stdout);
	ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
	JiKai_Thinks_ZiQi_Is_Delicious::main();
	return 0;
}