The first line contains a single integer *n* (1 ≤ *n* ≤ 1000) — the number of points on a plane.

Each of the next *n* lines contains two real coordinates *x*<sub class="lower-index">*i*</sub> and *y*<sub class="lower-index">*i*</sub> of the <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/1cec35c264f0a3aa9a2ce516deca3726f56c1544.png" style="max-width: 100.0%;max-height: 100.0%;"/> point, specified with exactly 2 fractional digits. All coordinates are between  - 1000 and 1000, inclusive.

Output a single real number θ — the answer to the problem statement. The absolute or relative error of your answer should be at most 10<sup class="upper-index"> - 2</sup>.
The first line contains a single integer *n* (1 ≤ *n* ≤ 1000) — the number of points on a plane.

Each of the next *n* lines contains two real coordinates *x*<sub class="lower-index">*i*</sub> and *y*<sub class="lower-index">*i*</sub> of the <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/1cec35c264f0a3aa9a2ce516deca3726f56c1544.png" style="max-width: 100.0%;max-height: 100.0%;"/> point, specified with exactly 2 fractional digits. All coordinates are between  - 1000 and 1000, inclusive.
n,num = int(input()),0
for i in range(n):
    num += float(input().split()[1])
print(f'{num / n + 5:.3f}')