#include <bits/stdc++.h>
using namespace std;

#define x first
#define y second
// #define int long long
#define mp(x, y) make_pair(x, y)
#define eb(...) emplace_back(__VA_ARGS__)
#define fro(i, x, y) for (int i = (x); i <= (y); i++)
#define pre(i, x, y) for (int i = (x); i >= (y); i--)
inline void JYFILE19();

bool ST;
const int N = 1e6 + 10;
const int mod = 998244353;

int n, m;
char s1[N], s2[N];
char t1[N], t2[N];

inline void solve() {
  cin >> n;
  cin >> (s1 + 1);
  cin >> (s2 + 1);
  cin >> (t1 + 1);
  cin >> (t2 + 1);
  int S1[2] = {}, F1[2] = {};
  int S2[2] = {}, F2[2] = {};
  int ns = 0;
  int l1 = 1, r1 = 1;
  int l2 = 1, r2 = 1;
  while (r1 <= n || r2 <= n) {
    if (r1 <= r2) {
      l1 = r1, S1[0] = S1[1] = F1[0] = F1[1] = 0;
      if (t1[r1] == '0') {
        S1[s1[r1] - '0']++, r1++;
      } else {
        for ( ; r1 <= n && t1[r1] == '1'; r1++) S1[s1[r1] - '0']++;
      }
    } else {
      l2 = r2, S2[0] = S2[1] = F2[0] = F2[1] = 0;
      if (t2[r2] == '0') {
        S2[s2[r2] - '0']++, r2++;
      } else {
        for ( ; r2 <= n && t2[r2] == '1'; r2++) S2[s2[r2] - '0']++;
      }
    }
    int l = max(l1, l2);
    int r = min(r1, r2) - 1;
    if (l <= r) {
      int sm = r - l + 1, o0 = 0, o1 = 0;
      auto chk1 = [&](int p) { return (S1[p] || (S1[p ^ 1] && F1[p])); };
      auto chk2 = [&](int p) { return (S2[p] || (S2[p ^ 1] && F2[p])); };
      auto del1 = [&](int p) { if (S1[p]) S1[p]--; else S1[p ^ 1]--, F1[p]--; };
      auto del2 = [&](int p) { if (S2[p]) S2[p]--; else S2[p ^ 1]--, F2[p]--; };
      auto get1 = [&](int p) { return S1[p] + min(S1[p ^ 1], F1[p]); };
      auto get2 = [&](int p) { return S2[p] + min(S2[p ^ 1], F2[p]); };
      while (sm && chk1(0) && chk2(0)) del1(0), del2(0), sm--, o0++, ns++;
      while (sm && chk1(1) && chk2(1)) del1(1), del2(1), sm--, o1++, ns++;
      int s = min(get1(1), get2(1));
      F1[1] += min(s, o0);
      F2[1] += min(s, o0);
    }
  }
  cout << ns << "\n";
}

signed main() {
  JYFILE19();
  int t;
  cin >> t;
  while (t--) solve();
  return 0;
}

bool ED;
inline void JYFILE19() {
  freopen("edit.in", "r", stdin);
  freopen("edit.out", "w", stdout);
  srand(random_device{}());
  ios::sync_with_stdio(0), cin.tie(0);
  double MIB = fabs(&ST-&ED) / 1000000, LIM = 512;
  cerr << MIB << " mib.\n", assert(MIB <= LIM);
}