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.*;

class Main{
    public static void main(String[] args) throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String str = br.readLine();
        String[] s = str.split(" ");
        int N = Integer.parseInt(s[0]);
        int Q = Integer.parseInt(s[1]);
        String str1 = "0" + br.readLine() + "0";
        String[][] td = new String[Q][2];
        for (int i=0;i<Q;i++){
            str = br.readLine();
            td[i] = str.split(" ");
        }
        System.out.println(B_search.b_search(N, str1, td, "R")-B_search.b_search(N, str1, td, "L"));
    }
}

class B_search{
    public static int b_search(int N,String str1,String[][] TD,String LR){
        int index = 0;
        int s = 0;
        int e = N+1;
        char c;
        String str;
        while (s!=e){
            index = (s+e)/2;
            for (int i=0;i<TD.length;i++){
                c = str1.charAt(index);
                str = String.valueOf(c);
                if (str.equals(TD[i][0])){
                    if (TD[i][1].equals("L")){
                        index--;
                    } else {
                        index++;
                    }
                }
                if (index<=0 || index>N){
                    break;
                }
            }
            if (LR.equals("L")){
                if (index<=0){
                    s = (s+e)/2+1;
                } else {
                    e = (s+e)/2;
                }
            } else {
                if (index>N){
                    e = (s+e)/2;
                } else {
                    s = (s+e)/2+1;
                }
            }
        }
        return s;
    }
}