#include <bits/stdc++.h>
#define int long long
using namespace std;
void solve() {
int n;
cin>>n;
string s;
cin>>s;
int i=n-1;
int ans=0;
int size=0;
int size2=0;
if(s[i]=='1'){
size++;
}
else if(s[i]=='0'){
size2++;
}
while(i>0){
if(s[i-1]=='1'){
size++;
}
else if(s[i-1]=='0'){
if(size){
if(size2){
ans+=2;
}
else{
ans++;
}
}
size=0;
size2++;
}
i--;
}
if(size){
if(size2){
ans+=2;
}
else{
ans++;
}
}
cout<<ans<<endl;
}
signed main() {
int t;
cin >> t;
while (t--) {
solve();
}
return 0;
}
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