text: // 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.
  
  function accum(s) {
    let arr = s.split('')
    let result = [];
    for (let i = 0; i < arr.length; i++) {
      result.push(arr[i].charAt(0).toUpperCase() + arr[i].toLowerCase().repeat(i));
    }
    return result.join('-');
  }
  