```
```

package com.codegym.task.task05.task0507;
import java.io.BufferedReader;
import java.io.InputStreamReader;
/*
Arithmetic mean
*/
public class Solution {
public static void main(String[] args) throws Exception {
//write your code here
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
String number = reader.readLine();
double average = 0;
int count = 0;
double sum = 0;
while(true){
count++;
int num =Integer.parseInt(number ) ;
if(num == -1)
sum+=num ;
average = sum/count;
System.out.println(average);
break;
}
}
}