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;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int q = sc.nextInt();
        String s = sc.next();
        char[] t = new char[q];
        char[] d = new char[q];
        for (int i = 0 ; i < q ; i++) {
            t[i] = sc.next().charAt(0);
            d[i] = sc.next().charAt(0);
        }
        int left = 0;
        int ng = n;
        int ok = -1;
        //残るゴーレムの一番左のインデックス
        while (Math.abs(ok  - ng) > 1) {
            int mid = (ok + ng) / 2;
            if (isDropable(mid, s, t, d)) {
                ok = mid;
            } else {
                ng = mid;
            }
            left = ng;
        }

        int right = n - 1;
        ng = -1;
        ok = n;
        //残るゴーレムの一番右のインデックス
        while (Math.abs(ok - ng) > 1) {
            int mid = (ng + ok) / 2;
            if (isDropable(mid, s, t, d)) {
                ok = mid;
            } else {
                ng = mid;
            }
            right = ng;
        }

        System.out.println(Math.max(right - left + 1, 0));

     }
    //選択したゴーレムが落ちるかどうか判定
    static boolean isDropable(int i, String s, char[] t, char[] d) {
        for (int j = 0 ; j < t.length ; j++) {
            if (s.charAt(i) == t[j]) {
                if (d[j] == 'L') {
                    i--;
                } else {
                    i++;
                }
            }
            if (i < 0 || i >= s.length()) {
                return true;
            }
        }
        return false;
    }

}