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.*;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    int q = sc.nextInt();
    String rawInput = sc.next();
    
    String input = "^" + rawInput + "$";
    char[] map = input.toCharArray();
    char[] ts = new char[q]; 
    char[] ss = new char[q]; 
    for (int i = 0; i < q; i++) {
      String t = sc.next();
      String s = sc.next();
      ts[i] = t.charAt(0);
      ss[i] = s.charAt(0);
    }
    
    int aliveMin = 1;
    int aliveMax = n;
    
    for (int i = q-1; i >= 0; i--) {
//      System.out.printf("i: %d, aliveMin: %d, aliveMax: %d\n", i, aliveMin, aliveMax);
      if (ss[i] == 'L') {
        if (map[aliveMin] == ts[i]) {
          aliveMin++;
        }
        if (map[aliveMax + 1] == ts[i]) {
          aliveMax++;
        }
      } else {
        if (map[aliveMin - 1] == ts[i]) {
          aliveMin--;
        }
        if (map[aliveMax] == ts[i]) {
          aliveMax--;
        }
      }
    }
//      System.out.printf("i: %d, aliveMin: %d, aliveMax: %d\n", 0, aliveMin, aliveMax);
    
    if (aliveMax >= aliveMin) {
      System.out.println(aliveMax - aliveMin + 1);
    } else {
      System.out.println(0);
    }
  }
}
