#include <stdio.h>
#include <stdlib.h>

typedef struct node{
    double element;
    struct node *next;
}node_t;

node_t *head = NULL;

node_t *add_first(double value, node_t *l){
    node_t *newNode = (node_t*)malloc(sizeof(node_t));
    newNode->element =value;
    newNode->next=l;
    return newNode;
}

int getSize(node_t *l){
    int size=0;
    for(node_t *i=head; i!=NULL; i=i->next){
        ++size;
    }
    return size;
}
double getSum(node_t *l){
    double value =0;
    for(node_t *i=head; i!=NULL; i=i->next){
        value += i->element;
    }
    return value;
}
double pop() {
    return head->element;
}
node_t *remove_first(node_t *l){
    node_t *newNode = l->next;
    free(l);
    return newNode;
}
int main()
{
    double input;
    double durchschnitt;
    double temp;
    while(input > 0){

        scanf("%lf", &input);
        head = add_first(input,head);
    }

    //remove negative numbers
    head = remove_first(head);

    durchschnitt = getSum(head)/getSize(head);

    for(node_t *i=head; i!=NULL; i=i->next){
        if(i->element < durchschnitt){
            temp += i->element;
        }
    }
    printf("%.2f", temp);
    for(node_t *i=head; i!=NULL; i=i->next){
        head=remove_first(head);
    }
    return 0;
}