#include <cmath>
#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <set>
#include <map>
#include <list>
#include <time.h>
#include <math.h>
#include <random>
#include <deque>
#include <queue>
#include <cassert>
#include <unordered_map>
#include <unordered_set>
#include <iomanip>
#include <bitset>
#include <sstream>
#include <chrono>
#include <cstring>

using namespace std;

#define rep(i,a,n) for (int i=a;i<n;i++)
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(),(x).end()
#define PI 3.14159265358979323846

typedef long long ll;
typedef long double ld;

void fastIO() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
}

const int mxn = 5e5 + 228;
int n;
int main() {
    fastIO();
    int tt;
    cin >> tt;
    while (tt--) {
        ll a, b, p;
        cin >> a >> b >> p;
        string s;
        cin >> s;
        vector<ll> ans(sz(s), 0);
        ll sum = 0;
        int res = sz(s);
        sum += (s[0] == 'A' ? a : b);
        ans[0] = sum;
        for (int i = 1; i < sz(s); ++i) {
            if (s[i] != s[i - 1]) {
                ans[i] = (s[i] == 'A' ? a : b);
            }
        }
        for (int i = sz(s) - 2; i >= 0; --i) {
            if (ans[i] > 0) {
                if (p - (s[i] == 'A' ? a : b) >= 0) {
                    p -= (s[i] == 'A' ? a : b);
                    res = i + 1;
                }
                else
                    break;
            }
        }
        cout << res << endl;
    }
}