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 sc = new Scanner(System.in);
		int n=sc.nextInt();
		int q =sc.nextInt();
		String s=sc.next();
		char[][] p=new char[q][2];
		for(int i=0; i<q; i++){
			String t=sc.next();
			p[i][0]=t.charAt(0);
			String k=sc.next();
			p[i][1]=k.charAt(0);
		}
		int countl=-1;
		for(int i=q-1; i>=0; i--){
			if(p[i][1]=='L'){
				if(countl+1==n){
					System.out.println(0);
					return;
				}
				if(p[i][0]==s.charAt(countl+1)){
					countl++;
				}
			}else{
				if(countl!=-1 && p[i][0]==s.charAt(countl)){
					countl=Math.max(-1,countl-1);
				}
			}
		}
		int countr=n;
		for(int i=q-1; i>=0; i--){
			if(p[i][1]=='L'){
				if(countr!=n && p[i][0]==s.charAt(countr)){
					countr=Math.min(n,countr+1);
				}
			}else{
				if(countr-1==-1){
					System.out.println(0);
					return;
				}
				if(p[i][0]==s.charAt(countr-1)){
					countr--;
				}
			}
		}
	
		System.out.println(n-countl-1-(n-countr));
	}
}
