#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef double db;
int n;
const int MAXN = 1e5+10;
char s1[MAXN],s2[MAXN],t1[MAXN],t2[MAXN];
int nxta[MAXN],nxtb[MAXN];

int work(){
    scanf("%d",&n);
    scanf("%s",s1+1);
    scanf("%s",s2+1);
    scanf("%s",t1+1);
    scanf("%s",t2+1);
    nxta[n+1]=nxtb[n+1]=n+1;
    t1[n+1]='0',t2[n+1]='0';
    for(int i=n;i;--i){
        if(t1[i+1]=='0'||t1[i]=='0')nxta[i]=i;
        else nxta[i]=nxta[i+1];
        if(t2[i+1]=='0'||t2[i]=='0')nxtb[i]=i;
        else nxtb[i]=nxtb[i+1];
    }
    int ans=0,ca1=0,ca2=0,cb1=0,cb2=0,w1=0,w2=0,p1=1,p2=1;
    while(p1<=n||p2<=n){
        if(p1<p2){
            int e=nxta[p1];
            while(p1<=e){
                ca1+=s1[p1]=='1';ca2+=s1[p1]=='0';
                ++p1;++w1;
            }
        }else{
            int e=nxtb[p2];
            while(p2<=e){
                cb1+=s2[p2]=='1',cb2+=s2[p2]=='0';
                ++p2;++w2;
            }
        }
        int d1=min({w1,ca1,cb1,w2}),d2=min({w1,w2,cb2,ca2});ans+=min({d1+d2,w1,w2});
        ca1-=min({d1,w1,w2});
        ca2-=min({d2,w1,w2});
        cb1-=min({d1,w1,w2});
        cb2-=min({d2,w1,w2});
        int d=min(w1,w2);
        w1-=d;
        w2-=d;
        if(p1>=p2)cb1=cb2=w2=0;
        if(p2>=p1)ca1=ca2=w1=0;
    }
    return ans;
}

int main(){
    freopen("edit.in","r",stdin);
    freopen("edit.out","w",stdout);
    int T;scanf("%d",&T);
    while(T--){
        cout<<work()<<endl;
    }
    return 0;
}