uri1261

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


int main()
{
    int dist , i=0 , soma=0;
    double media;
    char nome[30];
    while(gets(nome) != NULL && scanf("%d",&dist) != EOF)
    {
        soma += dist;
        i++;
    }
    media = soma / i;
    printf("%.1f\n" , media);
    return 0;
}