#include <stdio.h>
int main()
{
int a, b, c, d, e;
float avg;
scanf("%d %d %d %d %d",&a,&b,&c,&d,&e);
avg = (a+b+c+d+e)/5.0;
printf("%.1f",avg);
return 0;
}

#include <stdio.h>
int main()
{
int a, b, c, d, e;
float avg;
scanf("%d %d %d %d %d",&a,&b,&c,&d,&e);
avg = (a+b+c+d+e)/5.0;
printf("%.1f",avg);
return 0;
}