def smallestNumber(pattern: str) -> str:
    stack = []
    result = []
 
    # Iterate through the pattern and the last number
    for i in range(len(pattern) + 1):
        # Push the current number to the stack
        stack.append(str(i + 1))
 
        # If we reach the end or the current pattern is 'I', pop all from stack
        if i == len(pattern) or pattern[i] == 'I':
            while stack:
                result.append(stack.pop())
 
    return ''.join(result)
 
print(smallestNumber("IIIDIDDD"))

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

NDU=

45