any idea why I get the error cant find Symbol: BufferedReader?
package de.codegym.task.task05.task0507;
/*
Arithmetisches Mittel
*/
public class Solution {
public static void main(String[] args) throws Exception {
BufferedReader a = new BufferedReader(new InputStreamReader(System.in));
double b= Double.parseDouble(a.readLine());
double c=0;
double d=0;
if(b==-1){
System.out.println(c/d);
}
else{
c+=b;
d++;
}
}
}