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{
	public static void main(String[] args){
		Scanner s=new Scanner(System.in);
		int n=s.nextInt(),Q=s.nextInt();
		char[] c=s.next().toCharArray();

		char[] q=new char[Q];
		boolean[] f=new boolean[Q];
		for(int i=0;i<Q;++i){
			q[i]=s.next().charAt(0);
			f[i]=s.next().charAt(0)=='L';
		}

		int l=0,r=n;
		for(int i=Q-1;i>=0;--i){
			if(f[i]){
				if(l<n&&c[l]==q[i]) ++l;
				if(r<n&&c[r]==q[i]) ++r;
			}else{
				if(l>0&&c[l-1]==q[i]) --l;
				if(r>0&&c[r-1]==q[i]) --r;
			}
		}
		System.out.println(r-l);
	}
}
