package Ġcom . the evil root . postfix calculator . main Ċ Ċ import Ġcom . the evil root . postfix calculator . internal . Presenter Ċ Ċ interface ĠMain Presenter : ĠPres enter Ġ{ ĊĊĠĠĠ Ġfun Ġcalculate ( input String : ĠString ) Ċ Ċ }