```python
def run_decode(coded: -> str
    decoded = []
    i =   0
        if not coded[i            raise ValueError("Empty input")
        char = coded[i]
            if not char.isalpha():
                raise ValueError(f"Invalid character: {char}")
            count_str = ""
            while i + 1 <len(coded) and coded[i + 1).isdigit():
                count_str += coded[i + 1]
                i +=1
            if not count_str:
                raise ValueError(f"No count for character: {char}")
            count = int(count_str)
            if count <= 0:
                raise ValueError(f"Non-positive count for character:{char}: {count}")
            decoded.extend([char] * count)
        i +=1
    return "".join(decoded)
```