The input contains between 1 and 10 lines, *i*-th line contains an integer number *x*<sub class="lower-index">*i*</sub> (0 ≤ *x*<sub class="lower-index">*i*</sub> ≤ 9).
from sys import stdin,stdout
# from bisect import bisect_left,bisect
# from heapq import heapify,heappop,heappush
# from sys import setrecursionlimit
# from collections import defaultdict,Counter
# from itertools import permutations
# from math import gcd,ceil,sqrt,factorial
# setrecursionlimit(int(1e5))
input,print = stdin.readline,stdout.write

n = int(input())
ans = 0
win = 0
for i in range(1,n+1):
    x = int(input())
    win+=x
    ans = max(ans,win/i)
print(str(ans)+"\n")
