#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define pi pair<int,ll>
#define fi first
#define se second
#define pb push_back
#pragma GCC optimize("O3")
#pragma GCC target("avx2")


int main(){
    int t;cin>>t;
    while(t--){
        ll n;cin>>n;
        string s,t;cin>>s>>t;
        string ss="";
        int dif=0;
        for(int i=0;i<n;i++){
            if(s[i]!=t[i]){
                ss+='1';
            }else{
                ss+='0';
            }
        }
        dif+=(ss[0]=='1');
        for(int i=1;i<n;i++){
            if(ss[i]=='1'&&(ss[i-1]!=ss[i])){
                dif++;
            }
        }
        if(dif>2){
            cout<<0<<endl;
        }else if(dif==2){
            cout<<6<<endl;
        }else if(dif==1){
            if(n==1){
                cout<<0<<endl;
                continue;
            }
            int cnt=0;
            for(int i=0;i<n;i++){
                if(ss[i]=='1'){
                    for(int j=i;j<n&&ss[j]=='1';j++){
                        cnt++;
                    }
                    break;
                }
            }
            if(cnt==1){
                cout<<(n-1)*2<<endl;
            }else{
                cout<<(cnt-1+(n-cnt))*2<<endl;
            }

        }else{
            cout<<(n*(n+1))/2<<endl;
        }
    }
}