a=list(int(i) for i in input().split())

max=-1000
min=1000

for i in range(len(a)):
    if a[i]>max:
        max=a[i]
    if a[i]<min:
        min=a[i]
        
a.remove(max)
a.remove(min)

sum=0 
for i in range(len(a)):
    sum+=a[i]
    
print(sum/len(a))