def main():
    A = [[1]*26 for _ in range(26)]
    X = []
    u = 0
    for i in range(26):
        A[i][1] = 0
    while u < 26:
        for d in range(26):
            if not A[u][d]: continue
            while A[u][d]:
                A[u][d] = 0
                X.append((u, (u+d)%26))
                u = (u+d)%26
        X.append((u, (u+1)%26))
        u += 1
    for u, v in X:
        print(chr(65+u)+chr(65+v))
main()