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).
# Rishabh Rao (https://github.com/rishabhrao)

import sys
MOD = 1000000007
def inp(): return sys.stdin.readline().strip()
def ii(): return int(inp())
def iis(): return [int(i) for i in inp().split()]


foo, bar, baz, quz = 0, 0, 0, 1
tux = ii()
for _ in range(tux):
    pur = ii()
    foo += pur
    bar += 1
    if foo * quz > bar * baz:
        baz, quz = foo, bar
print(baz / quz)
