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A10419 | Vanya and Food Processor

时间限制1s
内存限制256MB
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题目描述

Vanya smashes potato in a vertical food processor. At each moment of time the height of the potato in the processor doesn't exceed $h$ and the processor smashes $k$ centimeters of potato each second. If there are less than $k$ centimeters remaining, than during this second processor smashes all the remaining potato.

Vanya has $n$ pieces of potato, the height of the $i$ -th piece is equal to $a_{i}$ . He puts them in the food processor one by one starting from the piece number $1$ and finishing with piece number $n$ . Formally, each second the following happens:

1. If there is at least one piece of potato remaining, Vanya puts them in the processor one by one, until there is not enough space for the next piece.
2. Processor smashes $k$ centimeters of potato (or just everything that is inside).

Provided the information about the parameter of the food processor and the size of each potato in a row, compute how long will it take for all the potato to become smashed.

输入格式

The first line of the input contains integers $n$ , $h$ and $k$ ( $1<=n<=100000,1<=k<=h<=10^{9}$ ) — the number of pieces of potato, the height of the food processor and the amount of potato being smashed each second, respectively.

The second line contains $n$ integers $a_{i}$ ( $1<=a_{i}<=h$ ) — the heights of the pieces.

输出格式

Print a single integer — the number of seconds required to smash all the potatoes following the process described in the problem statement.

输入输出样例

输入 #1
5 6 3
5 4 3 2 1
输出 #1
5
输入 #2
5 6 3
5 5 5 5 5
输出 #2
10
输入 #3
5 6 3
1 2 1 1 1
输出 #3
2
C++ 编辑器
输入
输出