#include <bits/stdc++.h> 
#define ll long long
using namespace std;
#define inf 1000000000000000005

int solve(int arr[],int a,int b,int i,int n,string s){
	if(i==n-2){
		if(s[i]=='A'){
			return arr[i] = a;
		}
		else{
			return arr[i] = b;
		}
	}
	if(s[i]==s[i+1]){
		return arr[i]=solve(arr,a,b,i+1,n,s);
	}
	else{
		if(s[i]=='A'){
			return arr[i] = a+solve(arr,a,b,i+1,n,s);
		}
		else{
			return arr[i] = b+solve(arr,a,b,i+1,n,s);
		}
	}
}

int main(){
#ifndef ONLINE_JUDGE
	freopen("input.txt","r",stdin);
	freopen("output.txt","w",stdout);	
#endif	
	int t;
	cin >> t;
	while(t--){
		int a,b,p;
		cin >> a>>b>>p;
		string s;
		cin >> s;
		int n = s.size();
		int arr[n];
		memset(arr,0,sizeof arr);
		int lol = solve(arr,a,b,0,n,s);
		int f = 0;
		int ret ;
		for(int i=0;i<n-1;i++){
			//cout<<arr[i]<<" ";
			if(arr[i]<=p){
				f = 1;
				ret = i+1;
				break;
			}
		}
		//cout<<"\n";
		if(f==1){
			cout<<ret<<"\n";
		}
		else{
			cout<<n<<"\n";
		}
	}
}