CF435A.Queue on Bus Stop

It's that time of the year when the Russians flood their countryside summer cottages (dachas) and the bus stop has a lot of people. People rarely go to the dacha on their own, it's usually a group, so the people stand in queue by groups.

The bus stop queue has n groups of people. The i-th group from the beginning has a__i people. Every 30 minutes an empty bus arrives at the bus stop, it can carry at most m people. Naturally, the people from the first group enter the bus first. Then go the people from the second group and so on. Note that the order of groups in the queue never changes. Moreover, if some group cannot fit all of its members into the current bus, it waits for the next bus together with other groups standing after it in the queue.

Your task is to determine how many buses is needed to transport all n groups to the dacha countryside.

又到了一年中的这个时候，俄罗斯人纷纷涌向乡间别墅（达恰），公交站台挤满了人。人们很少独自前往达恰，通常是以团体为单位出行，因此人们在队列中也是按团体站立。

公交站台的队列中共有 $n$ 个团体。从队首起第 $i$ 个团体有 $a_i$ 人。每 30 分钟有一辆空公交车抵达公交站台，每辆车最多可载 $m$ 人。显然，最前面团体的人先上车，然后是第二个团体，依此类推。注意：队列中各团体的相对顺序永远不会改变。此外，若某个团体无法全部登上当前这辆公交车，则该团体及其之后所有排在队列中的团体都将一同等待下一班车。

你的任务是计算出将全部 $n$ 个团体运送到达恰乡村所需的公交车数量。

The first line contains two integers n and m (1 ≤ n, m ≤ 100). The next line contains n integers: _a_1, _a_2, ..., a__n (1 ≤ a__i ≤ m).

第一行包含两个整数 $n$ 和 $m$（$1 \leq n, m \leq 100$）。下一行包含 $n$ 个整数：$a_1,\ a_2,\ \dots,\ a_n$（$1 \leq a_i \leq m$）。

Print a single integer — the number of buses that is needed to transport all n groups to the dacha countryside.

输出一个整数——将所有 $n$ 个小组运送到乡间别墅所需的巴士数量。