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).
# LUOGU_RID: 110679649
tux = int(input())
foo, bar, baz, quz = 0, 0, 0, 1
for i in range(1, tux + 1):
    pur = int(input())
    foo += pur
    baz += 1
    if foo * quz > baz * bar:
        baz = foo
        quz = bar
print(f'{baz / quz : .6f}')
