for _ in range(int(input())):
n,s=int(input()),input()
c=s[n//2]
for i in range(n//2,n):
if s[i]!=c:
break
else:i=n
print(2*i-n)#include<bits/stdc++.h>
using namespace std;
int t;
int main(){
cin>>t;
while(t--){
int n;
string s;
cin>>n>>s;
int k = n/2, i = k, j=k;
while(s[i+1]==s[k] and i<n-1)
i++;
while(j>=1 and s[j-1]==s[k])
j--;
cout<<i-j+1<<"\n";
}
}
///
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