There are n seats in the aircraft cabin in one row. For the convenience of passing and serving passengers, one or two passes are made along the cabin. For example, in the cabin of the Sukhoi Superjet 100 aircraft there are 5 seats in a row and one aisle (two seats on one side of the aisle, three on the other side), and in the largest modern aircraft — 10 seats and two aisles (three seats on the sides of the cabin at the windows and four seats between the aisles).
Suppose that in the future there will be larger aircraft, so the number of passes will have to be increased. Determine the minimum number of aisles in an airplane with n seats in one row of the cabin. On the sides of the cabin (at the windows) there can be no more than 3 seats, and between the two aisles — no more than 4 seats. At the same time, the cabin should
be at least one pass.
Input
The program receives as input one natural number n, not exceeding 2 · 10
9 , — the number of seats in one row of the salon.
Imprint
The program should output a single integer — the minimum number of aisles that must be in the cabin of an aircraft with n seats in one row.
Examples