#include <iostream>
#include <string>
#include <math.h>
#include <map>
#include <algorithm>
#include <vector>
#include <fstream>
#include <set>
#include <unordered_map>
#include <queue>
#include <climits>
#include <stack>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
#define LOOP(i,a,l) for (int i = a; i < l; i++)
#define LUO_VERKKO LOOP(i,0,m) {int a,b; cin >> a >> b; v[a].push_back(b); v[b].push_back(a);}
#define COLLECT for (int i = 0; i < n; i++) cin >> s[i]
#define PRINT_LIST(l) for (int i = 0; i < l.size(); i++) cout << l[i] << " "
#define S second
#define F first
#define A 999999999999999999LL
#define M 1000000007
//https://cses.fi/dt/
int n;
int k;
#define N (1<<17)
int main() {
cin >> n;
vector<int> bs;
for (int i = 0; i < n; i++)
{
string m; cin >> m;
int co = 0;
int len = m.length();
bs.clear();
int a = 0;
for (int j = 0; j < len; j++) {
if (m[j] == 'A') a++;
}
for (int j = 0; j < len; j++)
{
char c = m[j];
if (c == 'B') {
bs.push_back(j);
}
else {
if (bs.empty() || j < a) continue;
bs.erase(bs.begin());
co++;
}
}
cout << co << "\n";
}
}
