Finding Prefixes

A prefix of a string $S$ is a substring that starts at the very beginning of $S$. For example, the prefixes of $S$ = "codeplus" include "code", "co", "codepl", and "codeplus", while "plus", "s", "cude", and "crud" are not prefixes.

You are given a set $S$ of $N$ strings.

Write a program that counts how many of the $M$ given strings are a prefix of at least one string in the set $S$.

The first line contains the numbers of strings $N$ and $M$ ($1 \le N \le 10{,}000$, $1 \le M \le 10{,}000$).

Each of the next $N$ lines contains one string of the set $S$.

Each of the next $M$ lines contains one string to check.

Every string in the input consists only of lowercase English letters, and its length does not exceed 500. The set $S$ never contains the same string twice.

Print on the first line the number of the $M$ strings that are a prefix of at least one string in the set $S$.