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 {
	Scanner sc = new Scanner(System.in);
	
	public static void main(String[] args) {
		Main m = new Main();
		m.run();
	}
	
	void run() {
		int n = sc.nextInt();
		int q = sc.nextInt();

		char[] s = sc.next().toCharArray();
		char[] qt = new char[q];
		boolean[] ql = new boolean[q];

		for(int i = 0 ; i < q; i++) {
			qt[i] = sc.next().charAt(0);
			ql[i] = sc.next().charAt(0) == 'L'; 
		}
		int l = remLeft(s,qt,ql);
		int r = remRight(s,qt,ql);
		System.out.println(Math.max(0,r-l));
	}
	
	
	int remLeft(char[] s, char[]qt, boolean[] ql) {
		int l = 0;
		int r = s.length;
		for(;l!=r;) {
			int mid  = (l+r)/2;
			if(remL(s,qt,ql,mid)) {
				l = mid+1;
			}else {
				r = mid;
			}
		}
		return l;
	}

	int remRight(char[] s, char[]qt, boolean[] ql) {
		int l = 0;
		int r = s.length;
		for(;l!=r;) {
			int mid  = (l+r)/2;
			if(!remR(s,qt,ql,mid)) {
				l = mid+1;
			}else {
				r = mid;
			}
		}
		return l;
	}
	
	boolean remR(char[] s, char[] qt, boolean[] ql,int pos) {
		for(int i = 0; i < qt.length; i++) {
			if(pos == s.length) {
				return true;
			}
			if(s[pos] == qt[i]) {
				if(ql[i]) {
					pos--;
					pos = Math.max(0, pos);
				}else {
					pos++;
				}
			}
			
		}
		
		return pos == s.length;
				
	}

	boolean remL(char[] s, char[] qt, boolean[] ql,int pos) {
		for(int i = 0; i < qt.length; i++) {
			if(pos == -1) {
				return true;
			}
			if(s[pos] == qt[i]) {
				if(ql[i]) {
					pos--;
				}else {
					pos++;
					pos = Math.min(pos, s.length-1);
				}
			}
			
		}
		
		return pos == -1;
				
	}

}