Ural 1787. Turn for MEGA

1787. Turn for MEGA

Time limit: 1.0 second
Memory limit: 64 MB

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 approa
ching 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.

Input

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  a 1, …,  an (0 ≤  ai ≤ 100), where  aiis 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

Output the number of cars currently standing in the traffic jam.

Samples

input	output
5 3 6 7 2	0
5 3 20 0 0	5

Problem Author: Bulat Zaynullin
Problem Source: Ural Regional School Programming Contest 2010

每分钟可以通过k辆车

问n分钟后路上有几辆车

var n,k:integer;
var num:integer;
var ans:integer;
var i:integer;
begin
	read(k,n);
	ans:=0;
	for i:=1 to n do
	begin
		read(num);
		ans:=ans+num-k;
		if(ans<0) then ans:=0;
	end;
	writeln(ans);
end.

var n,k:integer;var num:integer;var ans:integer;var i:integer;beginread(k,n);ans:=0;for i:=1 to n dobeginread(num);ans:=ans+num-k;if(ans<0) then ans:=0;end;writeln(ans);end.