#include <bits/stdc++.h>
using namespace std;
int main() {
int t;
cin >> t;
while (t--) {
int n;
cin >> n;
string s;
cin >> s;
int maxConsecutive = 0;
int currentConsecutive = 0;
// Roy's move
for (int i = 0; i < n; i++) {
if (s[i] == '0') {
s[i] = '1';
currentConsecutive++;
maxConsecutive = max(maxConsecutive, currentConsecutive);
} else {
currentConsecutive = 0;
}
}
// Emon's move
for (int i = 0; i < n; i++) {
if (s[i] == '1') {
s[i] = '0';
currentConsecutive++;
maxConsecutive = max(maxConsecutive, currentConsecutive);
} else {
currentConsecutive = 0;
}
}
cout << maxConsecutive << endl;
}
return 0;
}