#include<bits/stdc++.h>
using namespace std;
const int maxn=1e5+5;
int T,n,c[3],d[3],ans;
int f[maxn],g[maxn];
char s[maxn],t[maxn];
char a[maxn],b[maxn];
int main(){
	freopen("edit.in","r",stdin);
	freopen("edit.out","w",stdout);
	scanf("%d",&T);while(T--){
		scanf("%d",&n);
		scanf("%s%s",s+1,t+1);
		scanf("%s%s",a+1,b+1);
		for(int i=n;i;i--){
			f[i]=a[i]=='1'&&a[i+1]=='1'?f[i+1]:i;
			g[i]=b[i]=='1'&&b[i+1]=='1'?g[i+1]:i;
		}
		for(int i=1,j=1,x;i<=n&&j<=n;){
			if(i<=j)for(int k=i;k<=f[i];k++)c[s[k]^48]++;
			if(i>=j)for(int k=j;k<=g[j];k++)d[t[k]^48]++;
			i=f[i];j=g[j];
			if(i==j){
				ans+=min(c[0],d[0]);
				ans+=min(c[1],d[1]);
				c[0]=c[1]=d[0]=d[1]=0;
				i++;j++;
			}else if(i>j){
				x=min(c[0],d[0]);
				ans+=x;c[0]-=x;d[0]-=x;
				x=min(c[1],d[1]);
				ans+=x;c[1]-=x;d[1]-=x;
				if(d[0])c[1]-=d[0],d[0]=0;
				if(d[1])c[0]-=d[1],d[1]=0;
				j++;s[i]='2';
			}else{
				x=min(c[0],d[0]); 
				ans+=x;c[0]-=x;d[0]-=x;
				x=min(c[1],d[1]);
				ans+=x;c[1]-=x;d[1]-=x;
				if(c[0])d[1]-=c[0],c[0]=0;
				if(c[1])d[0]-=c[1],c[1]=0;
				i++;t[j]='2';
			}
		}
		printf("%d\n",ans);
		ans=0;
	}
	return 0;
}