backspaces-in-string

Backspaces in string

Assume "#" is like a backspace in string. This means that string "a#bc#d" actually is "bd"

Your task is to process a string with "#" symbols.

Examples

"abc#d##c"      ==>  "ac"
"abc##d######"  ==>  ""
"#######"       ==>  ""
""              ==>  ""