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).
#input
n = int(input())
fo,br,bz,qu = 0,0,0,1
for i in range(n):
    p = int(input())
    fo = fo+p
    br = br+1
    if bz/qu<=fo/br:
        bz = fo
        qu = br
    else :
        break

print(bz/qu)