#include <iostream>
using namespace std;
 
int main() {
	int t;
	cin >> t;
	while(t--){
		char grid[3][3];
		for(int i=0; i<3; i++){
			for(int j=0; j<3; j++){
				cin>>grid[i][j];
			}
		}
		int f[3] = {0, 0, 0};
		for(int i=0; i<3; i++){
			for(int j=0; j<3; j++){
				if(grid[i][j] != '?'){
					int ind = grid[i][j] - 'A';
					f[ind]++;
				}
			}
		}
		if(f[0] == 2)cout << "A" << endl;
		else if(f[1] == 2)cout << "B" <<endl;
		else if(f[2] == 2)cout << "C" <<endl;
	}
	return 0;
}

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MwpBQkMKQz9CCkJDQQpCQ0EKQ0E/CkFCQwo/QUIKQkNBCkFCQwo=

3
ABC
C?B
BCA
BCA
CA?
ABC
?AB
BCA
ABC