N = int(input())
list1 = []
for i in range(N):
    list1.append(tuple(map(int, input().split())))
maxx = 0
for i in range(N):
    for j in range(i + 1, N):
        a = (list1[i][0] - list1[j][0]) ** 2 + (list1[i][1] - list1[j][1]) ** 2
        if maxx < a:
            maxx = a
print((maxx) ** 0.5)