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