This time no story, no theory. The examples below show you how to write function `accum`:
**Examples:**
```
accum("abcd") -> "A-Bb-Ccc-Dddd"
accum("RqaEzty") -> "R-Qq-Aaa-Eeee-Zzzzz-Tttttt-Yyyyyyy"
accum("cwAt") -> "C-Ww-Aaa-Tttt"
```
The parameter of accum is a string which includes only letters from `a..z` and `A..Z`.
def accum(s):
    str = ""
    for i in range(0, len(s)):
        str += s[i].upper()
        str += s[i].lower()*i
        if i != len(s)-1:
            str += "-"
    return str
def accum(s):
    str = ""
    for i in range(0, len(s)):
        str += s[i].upper()
        str += s[i].lower()*i
        if i != len(s)-1:
            str += "-"
    return str