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).
tux = input()
foo, bar, baz,quz = 0,0,0,1
tux = int(tux)
for i in range(tux):
    pur = int(input())
    foo+=pur
    bar+=1
    if foo*quz > bar*baz:
        baz = foo
        quz = bar

print(round(baz/quz,6))