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 {

    int n, q;
    String s;
    char[] ts, ds;

    void run() {
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt(); q = sc.nextInt();
        s = " " + sc.next();
        ts = new char[q];
        ds = new char[q];

        for (int i = 0; i < q; i++) {
            ts[i] = sc.next().charAt(0);
            ds[i] = sc.next().charAt(0);
        }

        int l = 0, r = n + 1;
        for (;l + 1 < r;) {
            int mid = (l + r) / 2;
            if (ok(mid, true)) {
                l = mid;
            } else {
                r = mid;
            }
//            debug(mid, ok(mid, false));
        }
//        debug(l);
        int cnt = l;
        l = 0; r = n + 1;
        for (;l + 1 < r;) {
            int mid = (l + r) / 2;
            if (ok(mid, false)) {
                r = mid;
            } else {
                l = mid;
            }
//            debug(mid, ok(mid, false));
        }
//        debug(r);
        cnt += n - r + 1;
        System.out.println(n - cnt);
    }

    boolean ok(int pos, boolean isLeft) {
        for (int i = 0; i < q; i++) {
            if (ts[i] == s.charAt(pos)) {
                if (ds[i] == 'L') {
                    pos--;
                } else {
                    pos++;
                }
            }
            if (pos <= 0 || pos > n) {
                return isLeft ^ pos >= n;
            }
        }
        return false;
    }


    void debug(Object...os) {
        System.err.println(Arrays.deepToString(os));
    }

    public static void main(String[] args) {
        new Main().run();
    }
}
