Seating
时间限制：C/C++/Rust/Pascal 1秒，其他语言2秒
空间限制：C/C++/Rust/Pascal 32 M，其他语言64 M
64bit IO Format: %lld

题目描述

To earn some extra money, the cows have opened a restaurant in their barn specializing in milkshakes. The restaurant has N seats (1 <= N <= 500,000) in a row. Initially, they are all empty. 
Throughout the day, there are M different events that happen in sequence at the restaurant (1 <= M <= 300,000). The two types of events that can happen are: 
1. A party of size p arrives (1 <= p <= N). Bessie wants to seat the party in a contiguous block of p empty seats. If this is possible, she does so in the lowest position possible in the list of seats. If it is impossible, the party is turned away. 
2. A range [a,b] is given (1 <= a <= b <= N), and everybody in that range of seats leaves. Please help Bessie count the total number of parties that are turned away over the course of the day.

输入描述:

* Line 1: Two space-separated integers, N and M.

* Lines 2..M+1: Each line describes a single event.  It is either a
line of the form "A p" (meaning a party of size p arrives) or
"L a b" (meaning that all cows in the range [a, b] leave).

输出描述:

* Line 1: The number of parties that are turned away.
示例1

输入

复制 
10 4
A 6
L 2 4
A 5
A 2

输出

复制 
1

说明

INPUT DETAILS:
There are 10 seats, and 4 events.  First, a party of 6 cows arrives.  Then
all cows in seats 2..4 depart.  Next, a party of 5 arrives, followed by a
party of 2.

OUTPUT DETAILS:
Party #3 is turned away.  All other parties are seated.