#include<bits/stdc++.h>
using namespace std;
#define fast ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define dbg(a,b,c,d) cerr<<a<<"  "<<b<<"  "<<c<<"  "<<d<<endl;
#define kill(a) {cout<<a<<endl;continue;}
#define KILL(a) {cout<<a<<endl;return 0;}
#define debug cerr<<"Error Found"<<endl;
#define mem(a,b) memset(a,b,sizeof(a))
#define lcm(a, b) (a/__gcd(a,b))*b
#define w(t) cin>>t;while(t--)
#define pi  2 * acos(0.0)
#define endl "\n"
int t, cs = 1;
const int mxn = 1e3 + 3, mod = 1e9 + 7;

int32_t main()
{
    //fast;
   w(t)
   {
       int n;
       cin >> n;
       string s;
       cin >> s;
       for(int i = 0; i < n; i++)if(s[i] == '1')s[i] = '0';else s[i] = '1';
       int ans = 0;
       for(int i = 0; i < n;)
       {
           int j = i, cnt = 0;
           while(i < n and s[j] == s[i])cnt++, i++;
           if(s[j] == '1')ans = max(ans, cnt);
       }
       cout << ans << endl;
   }


}