#include <bits/stdc++.h>

using namespace std;

void work () {
    int ans = 0;
    int n;
    string s1, s2, t1, t2;

    cin >> n;
    cin >> s1 >> s2 >> t1 >> t2;

    s1 = " " + s1, s2 = " " + s2, t1 = " " + t1, t2 = " " + t2;
    
    int a1=0, a2=0, b1=0, b2=0;

    int l = 1;
    for (int i=1; i<=n+1; i++) {
        if ( (t1[i] == '1' && t1[i-1] == '1') || (t1[i] == '1' && t2[i] == '1' && t2[i-1] == '1') || (t2[i] == '1' && t2[i-1] == '1') || (t2[i] == '1' && t1[i] == '1' && t1[i-1] == '1') ) {}

        else {
            // cout <<  << endl;
            a1=0, a2=0, b1=0, b2=0;
            for (int j=l; j<i; j++) {
                if (s1[j] == '1') a1++;
                if (s1[j] == '0') a2++;
                if (s2[j] == '1') b1++;
                if (s2[j] == '0') b2++;
            }
            l = i;
            ans = ans + min(a1, b1) + min(a2, b2);
        }


    }


    cout << ans << endl;

}


int main () {   
    int t;
    cin >> t;
    while (t--) {
        work();
    }



    return 0;
}

rt，假代码，但是民间数据可以80