import math 

n = int(input())
x = list(map(float, input().split()))
y = list(map(float, input().split()))
lx = len(x)
ly = len(y)

meanX = sum(x)/lx
meanY = sum(y)/ly

sdX = math.sqrt(sum([math.pow(xi-meanX, 2) for xi in x])/lx)
sdY = math.sqrt(sum([math.pow(yi-meanY, 2) for yi in y])/ly)


PCC = (sum((xi-meanX)*(yi-meanY) for xi, yi in zip(x, y)))/(n*sdX*sdY)

print(round(PCC, 3))