#include <bits/stdc++.h>
using namespace std;
#define int int64_t
signed main(void){
ios::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
#ifdef HELL_JUDGE
freopen("input","r",stdin);
freopen("output","w",stdout);
#endif
int t; cin >> t;
while (t--) {
int n; cin >> n;
string s; cin >> s;
deque<char>d;
d.push_back(s[0]);
map<char,int>m;
m['G'] =1;
m['R'] =2;
m['B'] =3;
map<int,char>rm;
rm[1] ='G';
rm[2] ='R';
rm[3] ='B';
for(int i=1 ; i<n; ++i) {
if(d.back() != s[i]) {
char ch = d.back(); d.pop_back();
ch = rm[m[ch]^m[s[i]]];
while (!d.empty() && d.back() != ch) {
char temp = d.back(); d.pop_back();
ch = rm[m[ch]^m[temp]];
}
d.push_back(ch);
} else {
d.push_back(s[i]);
}
}
cout << d.size() << '\n';
}
return 0;
}