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 in = new Scanner(System.in);
		int n = in.nextInt();
		int q = in.nextInt();
		String s = in.next();
		StringBuilder sb1 = new StringBuilder();
		StringBuilder sb2 = new StringBuilder();
		for(int i=0;i<q;i++) {
			sb1.append(in.next());
			sb2.append(in.next());
		}
		String t = sb1.toString();
		String d = sb2.toString();
		int ans = 0;
		//to_left
		int idx_l = 0;
		int idx_r = n-1;
		if(move(s,t,d,0)<0  && move(s,t,d,n-1)>=0) {
			while(idx_r-idx_l>1) {
				int idx_mid = (idx_l+idx_r)/2;
				int toward = move(s,t,d,idx_mid);
				if(toward<0) idx_l = idx_mid;
				else idx_r = idx_mid;
			}
			ans += idx_l+1;
		}else if(move(s,t,d,n-1)<0) {
			ans += n;
		}
		//to_right
		idx_l = 0;
		idx_r = n-1;
		if(move(s,t,d,0)<=0 && move(s,t,d,n-1)>0) {
			while(idx_r-idx_l>1) {
				int idx_mid = (idx_l+idx_r)/2;
				int toward = move(s,t,d,idx_mid);
				if(toward>0) idx_r = idx_mid;
				else idx_l = idx_mid;
			}
			ans += n-idx_r;
		}else if(move(s,t,d,0)>0) {
			ans += n;
		}
		System.out.println(n-ans);
		in.close();
	}
	
	public static int move(String s,String t,String d,int idx) {
		int n = s.length();
		int q = t.length();
		int ret = 0;
		for(int i=0;i<q;i++) {
			if(s.charAt(idx)==t.charAt(i)) {
				if(d.charAt(i)=='L') idx--;
				else idx++;
			}
			if(idx<0) {
				ret = -1;
				break;
			}
			if(idx>=n) {
				ret = 1;
				break;
			}
		}
		return ret;
	}

}
