candies2

Title

Problem Statement

There are N boxes arranged in a row. Initially, the i-th box from the left contains ai candies.

Snuke can perform the following operation any number of times:

  • Choose a box containing at least one candy, and eat one of the candies in the chosen box.

His objective is as follows:

  • Any two neighboring boxes contain at most x candies in total.

Find the minimum number of operations required to achieve the objective.

Constraints

  • 2 ≤ N ≤ 105
  • 0 ≤ ai ≤ 109
  • 0 ≤ x ≤ 109

Input

The input is given from Standard Input in the following format:

N x
a1 a2 ... aN

Output

Print the minimum number of operations required to achieve the objective.

Sample Input 1

3 3
2 2 2

Sample Output 1

1

Eat one candy in the second box. Then, the number of candies in each box becomes (2, 1, 2).

Sample Input 2

6 1
1 6 1 2 0 4

Sample Output 2

11

For example, eat six candies in the second box, two in the fourth box, and three in the sixth box. Then, the number of candies in each box becomes (1, 0, 1, 0, 0, 1).

Sample Input 3

5 9
3 1 4 1 5

Sample Output 3

0

The objective is already achieved without performing operations.

Sample Input 4

2 0
5 5

Sample Output 4

10

All the candies need to be eaten.


Submitting .cpp to 'candies2'


You're not logged in! Click here to login

Time Limit: 1 Seconds
Memory Limit: 1024MB
No. of ACs: 14
Your best score: 0
Source: ARC 064A

Subtask Score
1 100
2 0