#include <stdio.h>
int main() {
  struct Student {
    float high;
    char sex;
  } stu[5];
  int i;
  float s = 0;
  for (i = 0; i < 5; i++) {
    scanf("%f%c", &stu[i].high, &stu[i].sex);
    s += stu[i].high;
  }
  printf("平均身高为%f", s / 5);
  return 0;
}