import math
N  = int(input())
v = list(map(int,input().split(' ')))
#print(N,v)

v.sort(reverse=True)
#print(v[0])
vmax = v[0]
del v[0]
#print(v)
avg = sum(v)/len(v)
#print(avg,vmax)
print((avg+vmax)/2)