#include<bits/stdc++.h>
using namespace std;
const int N=1e5+5;
int T;
int n;
string s1,s2,t1,t2;
int cnt1[2],cnt2[2];
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--){
		cin>>n;
		cin>>s1>>s2>>t1>>t2;
		s1=" "+s1,s2=" "+s2;
		t1=" "+t1,t2=" "+t2;
		int i=1,j=1,ans=0;
		cnt1[0]=cnt1[1]=0;
		cnt2[0]=cnt2[1]=0;
		while(i<=n || j<=n){
			while(t1[i]!='0' && i<=n){
				cnt1[s1[i]-'0']++;
				i++;
			}
			while(t2[j]!='0' && j<=n){
				cnt2[s2[j]-'0']++;
				j++;
			}
			if(j<i){
				cnt2[s2[j]-'0']++;
				int mn0=min(cnt1[0],cnt2[0]),mn1=min(cnt1[1],cnt2[1]);
				ans+=mn0+mn1;
				cnt1[0]-=mn0;
				cnt1[1]-=mn1;
				cnt2[0]-=mn0;
				cnt2[1]-=mn1;
				if(cnt2[0]) cnt1[1]-=cnt2[0];
				if(cnt2[1]) cnt1[0]-=cnt2[1];
				cnt2[0]=cnt2[1]=0;
				j++;
				if(i==j) cnt1[0]=cnt1[1]=0;
			}
			else if(j>i){
				cnt1[s1[i]-'0']++;
				int mn0=min(cnt1[0],cnt2[0]),mn1=min(cnt1[1],cnt2[1]);
				ans+=mn0+mn1;
				cnt1[0]-=mn0;
				cnt1[1]-=mn1;
				cnt2[0]-=mn0;
				cnt2[1]-=mn1;
				if(cnt1[0]) cnt2[1]-=cnt1[0];
				if(cnt1[1]) cnt2[0]-=cnt1[1];
				cnt1[0]=cnt1[1]=0;
				i++;
			}
			else{
				if(i<=n) ans+=(s1[i]==s2[j]);
				int mn0=min(cnt1[0],cnt2[0]),mn1=min(cnt1[1],cnt2[1]);
				ans+=mn0+mn1;
				cnt1[0]-=mn0;
				cnt1[1]-=mn1;
				cnt2[0]-=mn0;
				cnt2[1]-=mn1;
				cnt1[0]=cnt1[1]=0;
				cnt2[0]=cnt2[1]=0;
				i++,j++;
			}
		}
		cout<<ans<<"\n";
	}
	return 0;
}
/*
1
4
1110
1011
1110
1011
*/