#include <bits/stdc++.h>
using namespace std;
#define ll long long int
#define ull unsigned long long
#define vecint vector<int>
#define vecchar vector<char>
#define un_set unordered_set
#define un_map unordered_map
#define max_ele(v) *max_element(v.begin(), v.end())
#define min_ele(v) *min_element(v.begin(), v.end())
#define sort_asc(v) sort(v.begin(), v.end())
#define sort_dec(v) sort((v).begin(), (v).end(), greater<>())
#define Reverse(v) reverse(v.begin(), v.end())
#define pb push_back
#define ppb pop_back()
#define pf push_front
#define coutall(v) \
for (auto &it : v) \
cout << it << " "
#define coutnewline(v) \
for (auto &it : v) \
cout << it << '\n'
#define cinall(v) \
for (auto &it : v) \
cin >> it
#define yes cout << "YES\n"
#define no cout << "NO\n"
constexpr char nl = '\n';
void solucionar()
{
int n, count = 0, max_ind = 0;
cin >> n;
string ch;
cin >> ch;
for (int i = 0; i < n; i++)
{
if (ch[i] == '0')
{
count++;
if (i == n - 1)
{
max_ind = max(max_ind, count);
count = 0;
}
}
else
{
max_ind = max(max_ind, count);
count = 0;
}
}
cout << max_ind << endl;
}
int main()
{
// ios_base::sync_with_stdio(false);
// cin.tie(0);
int tests;
cin >> tests;
while (tests-- > 0)
{
solucionar();
}
return 0;
}