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();
        char[] s = sc.next().toCharArray();
        char[][] spells = new char[Q][2];
        for (int i = 0; i < Q; i++) {
            spells[i][0] = sc.next().charAt(0);
            spells[i][1] = sc.next().charAt(0);
        }

        int ng=-1,ok=N;
        while( Math.abs(ng-ok) > 1){
            int mid = (ng+ok)/2;
            if(isOK(mid,spells,s) ==-1){
                ng = mid;
            }else{
                ok = mid;
            }
        }

        int leftOK = ok;

        ng=N;ok=-1;
        while( Math.abs(ng-ok) > 1){
            int mid = (ng+ok)/2;
            if(isOK(mid,spells,s) == 1){
                ng = mid;
            }else{
                ok = mid;
            }
        }

        int rightOK = N-1-ok;


        System.out.println( N - rightOK-leftOK);
    }

static    int isOK(int mid,char[][] spells ,char[] s ){
        for (int i = 0; i < spells.length; i++) {
            if(spells[i][0] == s[mid]){
                if(spells[i][1]=='L'){
                    mid--;
                }else{
                    mid++;
                }
                if(mid == -1) {
                    return -1;
                }
                if(mid == s.length) {
                    return 1;
                }
            }
        }
        return 0;
    }

}
