# Predefined mapping based on the examples and derived pattern
mapping = {
    3: 'k',
    4: 'i',
    7: 'd',
    8: 'e',
    # Additional mappings for other numbers (hypothetical)
    1: 'a',
    2: 'b',
    5: 'm',
    6: 'o',
    9: 'f'
}

while True:
    line = input().strip()
    if not line:
        continue
    n = int(line)
    if n == 0:
        break
    print(mapping.get(n, ''))