#include <bits/stdc++.h>
using namespace std;
const int N=100010;
int T,n,s10[N],s11[N],s20[N],s21[N],ans;
int f1[N],f2[N];
string s1,s2,t1,t2;
int find1(int x) {
    if (f1[x]==x) return x;
    return f1[x]=find1(f1[x]);
}
int find2(int x) {
    if (f2[x]==x) return x;
    return f2[x]=find2(f2[x]);
}
int main () {
    freopen("edit.in","r",stdin);
    freopen("edit.out","w",stdout); 
    ios::sync_with_stdio(0);
    cin.tie(0),cout.tie(0);
    cin >> T;
    while (T--) {
        memset(s10,0,sizeof(s10));
        memset(s11,0,sizeof(s11));
        memset(s20,0,sizeof(s20));
        memset(s21,0,sizeof(s21));
        ans=0;
        cin >> n;
        cin >> s1;
        cin >> s2;
        cin >> t1;
        cin >> t2;
        for (int i=1;i<=n;i++) f1[i]=f2[i]=i;
        for (int i=1;i<=n-1;i++) {
            if (t1[i-1]=='1'&&t1[i]=='1') f1[find1(i)]=find1(i+1);
            if (t2[i-1]=='1'&&t2[i]=='1') f2[find2(i)]=find2(i+1);
        }
        for (int i=0;i<n;i++) {
            if (s1[i]=='0') s10[find1(i+1)]++;
            if (s1[i]=='1') s11[find1(i+1)]++;
            if (s2[i]=='0') s20[find2(i+1)]++;
            if (s2[i]=='1') s21[find2(i+1)]++; 
        }
        for (int i=0;i<n;i++) {
            if (s10[find1(i+1)]>0&&s20[find2(i+1)]>0) {
                s10[find1(i+1)]--;
                s20[find2(i+1)]--;
                ans++;
            }else if (s11[find1(i+1)]>0&&s21[find2(i+1)]>0) {
                s11[find1(i+1)]--;
                s21[find2(i+1)]--;
                ans++;
            }
        }
        cout << ans <<endl;
    }
    return 0;
}