#include <stdio.h>
int main()
{
int score[5] = {0};
int i = 0, sum = 0;
for(i = 0;i < 5;i++)
{
scanf("%d", &score[i]);
sum += score[i];
}
double average = sum / 5.0;
printf("%.1lf", average); //取小数点后一位,记得使用%.1lf
return 0;
}