S = ["AB", "AC"]
C = ["B", "C"]
for _ in range(int(input())):
    n = int(input())
    ANS = []
    for i in range(n):
        ANS.append(S[i % 2])
    f = n % 2
    for i in range(n):
        ANS.append(C[(f + i) % 2])
    print(''.join(ANS))