昨天搜狗的一道题。。。。。（反正我挂了）

#!/bin/python
# -*- coding: UTF-8 -*-
import sys

"""搜狗题目，圆周上两点距离，
   第一行：输入n（圆上的n个点）  第二行：输入n个点的度数s（0<=s<=360） 双精度，8位小数
   输出园中距离最远的两点之间的夹角度数m（0<=m<=180）,双精度，保留8位小数
"""
n = input()
circle = []
for i in range(n):
    doublenum = sys.stdin.readline().strip()
    doublenum = float(doublenum)
    circle.append(doublenum)

"""二分查找寻找下届，恰好小于key"""
def Binery_Find(circle,n,key):
    low = 0
    high = n-1
    mid = (low + high) / 2
    while low < high:
        if circle[mid]< key :
            low = mid
        else:
            high = mid -1
        mid = (low + high+1) / 2
    return mid
maxx = 0
for i in range(n-1):
    key = circle[i]+180
    if key > 360:
        key -= 360
    mid1 = Binery_Find(circle,n,key)
    mid2 = mid1+1
    if mid1< n-1:
        maxx = max(circle[mid1]-circle[i],maxx,360-(circle[mid2]-circle[i]))
    else:
        maxx = max((circle[mid1] - circle[i]), maxx)
print "%.8f"%maxx