#include <stdio.h>
int main(void)
{
 int i;
 double height[5];
 double total = 0.0;

 for(i = 0; i < 5; i++)
 {
  scanf("%lf", &height[i]);
 }

 for(i = 0; i < 5; i++)
 {
  total += height[i];
 }
 printf("average = %.1f\n", total / 5);
 return 0;
}