#include<bits/stdc++.h>
using namespace std;
const int N=1e5+10;
char a[N],b[N],ai[N],bi[N];
int num1[N],num0[N];
int sum1[N],sum0[N];
int st1[N],st2[N];
int _T,n;
int cnt1,cnt2;
void init(){
    memset(num1,0,sizeof(num1));
    memset(num0,0,sizeof(num0));
    memset(sum1,0,sizeof(sum1));
    memset(sum0,0,sizeof(sum0));
    cnt1=cnt2=0;
}
int main(){
    freopen("edit.in","r",stdin);
    freopen("edit.out","w",stdout);
    scanf("%d",&_T);
    while(_T--){
        init();
        scanf("%d",&n);
        scanf("%s",a+1);scanf("%s",b+1);
        scanf("%s",ai+1);scanf("%s",bi+1);
        ai[n+1]='0';bi[n+1]='0';
        a[n+1]='0',b[n+1]='0';
        int tmp1=0,tmp2=0;
        for(int i=1;i<=n+1;i++){
            if(a[i]=='1')tmp1++;
            else tmp2++;
            if(ai[i]=='0'){
                st1[++cnt1]=i;
                num1[i]=tmp1,num0[i]=tmp2;
                tmp1=tmp2=0;
            }
        }
        tmp1=tmp2=0;
        for(int i=1;i<=n+1;i++){
            if(b[i]=='1')tmp1++;
            else tmp2++;
            if(bi[i]=='0'){
                st2[++cnt2]=i;
                sum1[i]=tmp1,sum0[i]=tmp2;
                tmp1=tmp2=0;
            }
        }
        int s=1,f=1;
        int ans=0;
        int tmp3=0,tmp4=0;
        while(s<=cnt1 && f<=cnt2){
            int opt=-1;
            if(st2[f]<st1[s]){
                tmp1=sum1[st2[f]],tmp2=sum0[st2[f]];
                tmp3=num1[st1[s]],tmp4=num0[st1[s]];
                if(a[st1[s]]=='1')tmp3--;
                else tmp4--;
                int res1=min(tmp1,tmp3),res2=min(tmp2,tmp4);
                
                if(tmp1>tmp3){
                    num0[st1[s]]-=(tmp1-tmp3);
                }
                num1[st1[s]]-=res1;
                if(tmp2>tmp4){
                    num1[st1[s]]-=(tmp2-tmp4);
                }
                num0[st1[s]]-=res2;


                ans+=res1+res2;
                opt=1;
            }
            else if(st2[f]>st1[s]){
                tmp1=sum1[st2[f]],tmp2=sum0[st2[f]];
                tmp3=num1[st1[s]],tmp4=num0[st1[s]];
                if(b[st2[f]]=='1')tmp1--;
                else tmp2--;
                int res1=min(tmp1,tmp3),res2=min(tmp2,tmp4);

                if(tmp1<tmp3){
                    sum0[st2[f]]-=(tmp3-tmp1);
                }
                sum1[st2[f]]-=res1;
                if(tmp2<tmp4){
                    sum1[st2[f]]-=(tmp4-tmp2);
                }
                sum0[st2[f]]-=res2;

                ans+=res1+res2;
                opt=2;
            }
            else if(st2[f]==st1[s]){
                if(b[st2[f]]==a[st1[s]])ans++;
                tmp1=sum1[st2[f]],tmp2=sum0[st2[f]];
                tmp3=num1[st1[s]],tmp4=num0[st1[s]];
                if(b[st2[f]]=='1')tmp1--;
                else tmp2--;
                if(a[st1[s]]=='1')tmp3--;
                else tmp4--;

                int res1=min(tmp1,tmp3),res2=min(tmp2,tmp4);

                if(a[st1[s]]=='1'){num1[st1[s]]=1;num0[st1[s]]=0;}
                else {num1[st1[s]]=0;num0[st1[s]]=1;}

                if(b[st2[f]]=='1'){sum1[st2[f]]=1;sum0[st2[f]]=0;}
                else {sum1[st2[f]]=0;sum0[st2[f]]=1;}

                ans+=res1+res2;
                opt=3;
            }
            if(opt==1)f++;
            else if(opt==2)s++;
            else f++,s++;
        }
        cout<<ans-1<<'\n';
    }



    return 0;
}