```python
def run_decode(coded: -> str
    decoded = []
    i =   0
        if coded[i            char = coded[i]
            count_start = i + 1
            while count_start < len(coded) and coded[count_start].isdigit():
                count_start += 1
            count = int(coded[i:i:count_start])
            decoded.extend([char] * count)
            i = count_start
        else:
            raise ValueError("Invalid input:    return ''.join(decoded)
```