#include<bits/stdc++.h>

#define MAXN 100005

int T;
int n;
char s1[MAXN],s2[MAXN];
char t1[MAXN],t2[MAXN];
int ans=0;
int l1,l2;
int c1[2],c2[2];

int main(){
    std::ios::sync_with_stdio(false);

    freopen("edit.in","r",stdin);
    freopen("edit.out","w",stdout);

    std::cin>>T;
    for(int i=1;i<=T;i++){
        ans=0;

        std::cin>>n;
        std::cin>>(s1+1)>>(s2+1);
        std::cin>>(t1+1)>>(t2+1);

        l1=l2=0;
        c1[0]=c1[1]=c2[0]=c2[1]=0;

        while(l1<n||l2<n){
            if(c1[0]+c1[1]==0){
                ++l1;
                if(t1[l1]=='0'){
                    c1[s1[l1]-'0']++;
                }else{
                    c1[s1[l1]-'0']++;
                    while(t1[l1+1]=='1') ++l1,c1[s1[l1]-'0']++;
                }
            }
            if(c2[0]+c2[1]==0){
                ++l2;
                if(t2[l2]=='0'){
                    c2[s2[l2]-'0']++;
                }else{
                    c2[s2[l2]-'0']++;
                    while(t2[l2+1]=='1') ++l2,c2[s2[l2]-'0']++;
                }
            }
            if(c1[0]&&c2[0]){
                int x=std::min(c1[0],c2[0]);
                c1[0]-=x,c2[0]-=x,ans+=x;
            }
            if(c1[1]&&c2[1]){
                int x=std::min(c1[1],c2[1]);
                c1[1]-=x,c2[1]-=x,ans+=x;
            }
            if(c1[0]&&c2[1]){
                int x=std::min(c1[0],c2[1]);
                c1[0]-=x,c2[1]-=x;
            }
            if(c1[1]&&c2[0]){
                int x=std::min(c1[1],c2[0]);
                c1[1]-=x,c2[0]-=x;
            }
        }
        std::cout<<ans<<'\n';
    }

    return 0;
}