B. George and Round
time limit per test
1 second
memory limit per test
256 megabytes
standard input
standard output

George decided to prepare a Codesecrof round, so he has prepared m problems for the round. Let's number the problems with integers 1 through m. George estimates the i-th problem's complexity by integer b i.

To make the round good, he needs to put at least n problems there. Besides, he needs to have at least one problem with complexity exactly a 1, at least one with complexity exactly a 2, ..., and at least one with complexity exactly a n. Of course, the round can also have problems with other complexities.

George has a poor imagination. It's easier for him to make some already prepared problem simpler than to come up with a new one and prepare it. George is magnificent at simplifying problems. He can simplify any already prepared problem with complexity c to any positive integer complexity d ( c ≥ d), by changing limits on the input data.

However, nothing is so simple. George understood that even if he simplifies some problems, he can run out of problems for a good round. That's why he decided to find out the minimum number of problems he needs to come up with in addition to the m he's prepared in order to make a good round. Note that George can come up with a new problem of any complexity.


The first line contains two integers n and m (1 ≤ n, m ≤ 3000) — the minimal number of problems in a good round and the number of problems George's prepared. The second line contains space-separated integers a 1, a 2, ..., a n (1 ≤ a 1 < a 2 < ... < a n ≤ 106) — the requirements for the complexity of the problems in a good round. The third line contains space-separated integers b 1, b 2, ..., b m (1 ≤ b 1 ≤ b 2... ≤ b m ≤ 106) — the complexities of the problems prepared by George.


Print a single integer — the answer to the problem.

3 5
1 2 3
1 2 2 3 3
3 5
1 2 3
1 1 1 1 1
3 1
2 3 4

In the first sample the set of the prepared problems meets the requirements for a good round.

In the second sample, it is enough to come up with and prepare two problems with complexities 2 and 3 to get a good round.

In the third sample it is very easy to get a good round if come up with and prepare extra problems with complexities: 2, 3, 4.