# Read input
N, D = map(int, input().split())

# Initialize hole counts for each character
hole = [0] * 26  # Index 0 for 'A', 1 for 'B', ..., 25 for 'Z'

# Set holes for 'B'
hole[ord('B') - ord('A')] = 2

# Set holes for characters with 1 hole
for c in ['A', 'D', 'O', 'P', 'Q', 'R']:
    hole[ord(c) - ord('A')] = 1

result = []
current_sum = 0

for i in range(N):
    m = N - i - 1  # Remaining characters after current
    # Iterate through each character from 'A' to 'Z'
    for c_ord in range(ord('A'), ord('Z') + 1):
        c = chr(c_ord)
        k = hole[c_ord - ord('A')]
        new_sum = current_sum + k
        required = D - new_sum
        if required < 0:
            continue
        # Check if remaining required holes can be achieved with m characters
        if 0 <= required <= 2 * m:
            result.append(c)
            current_sum = new_sum
            break

print(''.join(result))