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).
#in the name of god
#Mr_Rubik
#http://codeforces.com/problemset/problem/290/C
foo=baz=0;quz=1
for bar in range(1, int(input()) + 1):
    foo+=int(input())
    if foo*quz<baz*bar: 
        break
    baz,quz=foo,bar
print(baz / quz)