The examples below show you how to write function accum: Examples: accum("abcd"); // output: "A-Bb-Ccc-Dddd" accum("RqaEzty"); // output: "R-Qq-Aaa-Eeee-Zzzzz-Tttttt-Yyyyyyy" accum("cwAt"); // output: "C-Ww-Aaa-Tttt" The parameter of accum is a string which includes only letters from a..z and A..Z.