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 {
	static int num;
	static int magic;
	static int type[] = new int[(int)200100];
	static int opponent[] = new int[(int)200100];
	static boolean isL[] = new boolean[(int)200100];
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		num = sc.nextInt();
		magic = sc.nextInt();
		String oppos = sc.next();
		for(int i = 0; i < num; i ++) {
			type[i] = oppos.charAt(i) - 'A';
		}
		for(int i = 0; i < magic; i ++) {
			opponent[i] = sc.next().charAt(0) - 'A';
			isL[i] = sc.next().charAt(0) == 'L' ? true : false;
		}
		System.out.println(Math.max(bisect(true) - bisect(false) - 1, 0));
	}

	static int bisect(boolean max) {
		int ng = max ? -1 : num;
		int ok = max ? num : -1;
		while (Math.abs(ok - ng) > 1) {
			int mid = (ok + ng) / 2;
			if(isOK(mid)) {
				ok = mid;
			}else {
				ng = mid;
			}
		}
		return ok;
	}
	static boolean isOK(int index) {//will dissapear
		for(int i = 0; i < magic; i ++) {
			if(opponent[i] == type[index]) {
				index += isL[i] ? -1 : 1;
			}
			if(index == -1 || index == num) {
				return true;
			}
		}
		return false;
	}
}