Write a program to edit a word. First you will be given a word consisting of lower letters. Each line afterward is a command. The commands are as follow.

• replace x y
  Both $x$ and $y$ are character. You need to replace all occurrence of $x$ by $y$.
• remove x
  Remove all occurrence of $x$.
• addhead x
  Add a character $x$ at the beginning of the word.
• addtail x
  Add a character $x$ at the end of the word.
• end
  Stop the computation. It is guarantee the last command is always an end.

For example, if you are given a word "pangfeng", then after "replace g d" you will have "pandfend". Then after "remove n" you will have "padfed". After "addhead a" you will have "apadfed". After "addtail s" you will have "apadfeds".