There are N squares numbered 1 to N from left to right. Each square has a character written on it, and Square i has a letter s_i. Besides, there is initially one golem on each square.

Snuke cast Q spells to move the golems.

The i-th spell consisted of two characters t_i and d_i, where d_i is `L` or `R`. When Snuke cast this spell, for each square with the character t_i, all golems on that square moved to the square adjacent to the left if d_i is `L`, and moved to the square adjacent to the right if d_i is `R`.

However, when a golem tried to move left from Square 1 or move right from Square N, it disappeared.

Find the number of golems remaining after Snuke cast the Q spells.

Constraints

* 1 \leq N,Q \leq 2 \times 10^{5}
* |s| = N
* s_i and t_i are uppercase English letters.
* d_i is `L` or `R`.

Input

Input is given from Standard Input in the following format:


N Q
s
t_1 d_1
\vdots
t_{Q} d_Q


Output

Print the answer.

Examples

Input

3 4
ABC
A L
B L
B R
A R


Output

2


Input

8 3
AABCBDBA
A L
B R
A R


Output

5


Input

10 15
SNCZWRCEWB
B R
R R
E R
W R
Z L
S R
Q L
W L
B R
C L
A L
N L
E R
Z L
S L


Output

3
import java.util.Scanner;
import java.util.Stack;

public class Main {
  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);

    int N = scanner.nextInt();
    int Q = scanner.nextInt();
    char[] s = scanner.next().toCharArray();
    char[][] queries = new char[Q][2];
    for (int i = 0; i < Q; i++) {
      queries[Q - i - 1][0] = scanner.next().charAt(0);
      queries[Q - i - 1][1] = scanner.next().charAt(0);
    }

    Stack<Character> stack = new Stack<>();
    int i = s.length - 1;
    for (int j = 0; j < Q; j++) {
      if (i >= 0 && s[i] == queries[j][0] && queries[j][1] == 'R') {
        stack.push(s[i]);
        i--;
      }
      if (!stack.isEmpty() && stack.peek() == queries[j][0] && queries[j][1] == 'L') {
        stack.pop();
        i++;
      }
    }
    int mr = stack.size();

    stack.clear();
    i = 0;
    for (int j = 0; j < Q; j++) {
      if (i < N && s[i] == queries[j][0] && queries[j][1] == 'L') {
        stack.push(s[i]);
        i++;
      }
      if (!stack.isEmpty() && stack.peek() == queries[j][0] && queries[j][1] == 'R') {
        stack.pop();
        i--;
      }
    }
    int ml = stack.size();

    System.out.println(N - Math.min(ml + mr, N));
  }
}
