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.io.*;
import java.util.*;

public class Main {
    static int[] color;
    static int[][] order;
    static int n,Q;
    public static void main(String[] args)throws IOException {
        Scanner sc = new Scanner(System.in);
        //BufferedReader reader = new BufferedReader(new InputStreamReader(in));
        n = sc.nextInt(); Q = sc.nextInt();
        order = new int[Q][2];
        color = new int[n];
        char[] s = sc.next().toCharArray();
        for(int i=0;i<n;i++) color[i]=s[i]-'A';
        for(int i=0;i<Q;i++){
            int cur = sc.next().charAt(0)-'A';
            int dir = sc.next().charAt(0)=='L'?-1:1;
            order[i][0] = cur; order[i][1] = dir;
        }
        // find the idx left
        int left;
        if(!exitFromLeft(0)) left = 0;
        else{
            if(exitFromLeft(n-1)) left = n;
            else{
                int hi = n-1, lo = 0;
                while(hi-lo>1){
                    int mid = (hi+lo)/2;
                    if(exitFromLeft(mid)) lo=mid;
                    else hi = mid;
                }
                left = hi;
            }
        }
        int right;
        if(!exitFromRight(n-1)) right = n-1;
        else{
            if(exitFromRight(0)) right = -1;
            else{
                int hi = n-1, lo = 0;
                while(hi-lo>1){
                    int mid = (hi+lo)/2;
                    if(exitFromRight(mid)) hi=mid;
                    else lo = mid;
                }
                right = lo;
            }
        }
        System.out.println(Math.max(0,right-left+1));
    }
    static boolean exitFromLeft(int idx){
        int pos = idx;
        for(int i=0;i<Q;i++){
            if(order[i][0]!=color[pos]) continue;
            pos += order[i][1];
            if(pos==n) return false;
            if(pos<0) return true;
        }
        return false;
    }
    static boolean exitFromRight(int idx){
        int pos = idx;
        for(int i=0;i<Q;i++){
            if(order[i][0]!=color[pos]) continue;
            pos += order[i][1];
            if(pos==n) return true;
            if(pos<0) return false;
        }
        return false;
    }
}