A traffic light at the turn for the “MEGA” shopping center from the
Novomoskovskiy highway works in such a way that k cars are able to
take a turn in one minute. At weekends all the residents of the city
drive to the mall to take a shopping, which results in a huge traffic
jam at the turn. Administration of the mall ordered to install a camera
at the nearby bridge, which is able to calculate the number of cars
approaching this turn from the city. The observation started n minutes ago.
You should use the data from the camera to determine the number of cars
currently standing in the traffic jam.
The first line contains integers k and n (1 ≤ k, n ≤ 100), which
are the number of cars that can take a turn to “MEGA” in one minute
and the number of minutes passed from the beginning of observation.
The second line contains space-separated integers a1, …, an
(0 ≤ ai ≤ 100), where ai is the number of cars that approached the turn
during the i-th minute. The observation started at morning, when there
were no cars at the turn.
Output the number of cars currently standing in the traffic jam.
6 7 2
20 0 0
Problem Author: Bulat Zaynullin
Problem Source: Ural Regional School Programming Contest 2010