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 tiles = sc.next();
        String[] t = new String[q];
        String[] d = new String[q];
        for(int i=0;i<q;i++) {
            t[i] = sc.next();
            d[i] = sc.next();
        }
        // for(int i=0;i<q;i++) System.out.println(t[i]);
        // for(int i=0;i<q;i++) System.out.println(d[i]);
        int ok = -1;
        int ng = n;
        while(ok < ng - 1) {
            int mid = (ok+ng)/2;
            // System.out.println(mid);
            if (leftOut(mid, q, tiles, t, d)) {
                // System.out.println("Leftout");
                ok = mid;
            } else {
                // System.out.println("NotLeftout");
                ng = mid;
            }
        }
        int leftOutMax = ok;
        ng = -1;
        ok = n;
        while(ok > ng + 1) {
            int mid = (ok+ng)/2;
            // System.out.println(mid);
            if (rightOut(mid, q, tiles, t, d)) {
                // System.out.println("Leftout");
                ok = mid;
            } else {
                // System.out.println("NotLeftout");
                ng = mid;
            }
        }
        int rightOutMin = ok;
        int answer;
        if (rightOutMin < leftOutMax) {
            answer = n;
        } else {
            answer = leftOutMax + 1 + (n-rightOutMin);
        }
        System.out.println(n-answer);
    }
    public static boolean leftOut(int startIndex, int directionNum, String tile, String[] directionT, String[] directionLR) {
        int tileLength = tile.length();
        if (startIndex < 0) return(true);
        if (startIndex >= tileLength) return(false);
        char currentTile = tile.charAt(startIndex);    
        int currentIndex = startIndex;
        for(int i=0;i<directionNum;i++){
            String target = directionT[i];
            char direction = directionLR[i].charAt(0);
            // System.out.println(direction);
            if (target.charAt(0) != currentTile) {
                continue;
            }
            if (direction == 'L') {
                currentIndex--;
                // System.out.println(currentIndex);
            } else if (direction == 'R') {
                currentIndex++;
                // System.out.println(currentIndex);
            } else {
                // System.out.println("ERROR");
            }
            if (currentIndex < 0) {
                return(true);
            } else if (currentIndex >= tileLength) {
                return(false);
            } else {
                currentTile = tile.charAt(currentIndex);
            }
        }
        return(false);
    }
    public static boolean rightOut(int startIndex, int directionNum, String tile, String[] directionT, String[] directionLR) {
        int tileLength = tile.length();
        if (startIndex < 0) return(false);
        if (startIndex >= tileLength) return(true);
        char currentTile = tile.charAt(startIndex);    
        int currentIndex = startIndex;
        for(int i=0;i<directionNum;i++){
            String target = directionT[i];
            char direction = directionLR[i].charAt(0);
            if (target.charAt(0) != currentTile) {
                continue;
            }
            if (direction == 'L') {
                currentIndex--;
            } else if (direction == 'R') {
                currentIndex++;
            } else {
            }
            if (currentIndex < 0) {
                return(false);
            } else if (currentIndex >= tileLength) {
                return(true);
            } else {
                currentTile = tile.charAt(currentIndex);
            }
        }
        return(false);
    }
}