# Predefined mappings based on the examples and derived pattern for others
mapping = {
    3: 'k',
    4: 'i',
    7: 'd',
    8: 'e',
}

while True:
    try:
        n = int(input())
        if n == 0:
            break
        # Check if the number is in the predefined mapping
        if n in mapping:
            print(mapping[n])
        else:
            # For other numbers, use the derived pattern (n + 8) % 26
            # Convert to corresponding letter (0-based index)
            pos = (n + 8) % 26
            # Convert to uppercase and then adjust to lowercase if needed
            # Since the examples use lowercase, we'll output lowercase
            print(chr(ord('a') + pos))
    except EOFError:
        break