Arranging Cats

 
#include <bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
// using namespace __gnu_pbds;
using namespace std;
 
#define ll long long
#define pb push_back
// #define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
#define dbg(x) cout << #x << " = " << x << "\n";
#define all(x) (x).begin(),(x).end()
#define ff first
#define ss second
#define srt(s) sort(all(s))
#define S size()
#define f(i,m,n) for(ll i=m;i<n;i++)
#define nf(i,b,a); for(ll i=(b);i>=(a);i--)
#define llv(a,n) vector<ll> a(n,0); for(ll i=0;i<n;i++) cin>>a[i];
#define test(v) for(auto i:v) cout<<i<<' '; cout<<endl;
 
//__builtin_popcountll(x)
//msb 63 - __builtin_clzll(x) most(largest)
//lsb __builtin_ctzll(x)
 
//think again
 
void solve(){
    ll a; cin>>a; string s,q;  cin>>s>>q;
    ll c=0, cc=0;
    f(i,0,a){
        if(s[i]=='1' and q[i]=='0'){
            c++;
        }else if(s[i]=='0' and q[i]=='1'){
            cc++;
        }
    } 
    cout<<min(c,cc)+abs(cc-c)<<endl;
}
 
int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    ll t;cin>>t;
    while(t--)
       solve();
    return 0;
}