Could someone explain me why the error occurs when I run my code ? (edit : line 16 is of course: while (wprowadzonaLiczba != -1). (pl/codegym/task/task05/task0507/Solution.java:9: error: cannot find symbol BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); ^ symbol: class BufferedReader location: class pl.codegym.task.task05.task0507.Solution)