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 sc = new Scanner(System.in);
		int N = sc.nextInt();
		int Q = sc.nextInt();
		char[] s = sc.next().toCharArray();
		int[] ss = new int[N];
		for(int i=0; i<N; i++)
			ss[i] = s[i]-'A';
		
		int[] t = new int[Q];
		int[] d = new int[Q];
		for(int i=0; i<Q; i++) {
			t[i] = sc.next().toCharArray()[0]-'A';
			d[i] = sc.next().equals("L") ? -1 : 1;
		}
		
		int ll = -1;
		int lr = N;
		while(ll+1 < lr) {
			int mid = (ll+lr)/2;
			if(exceedLeft(N, ss, Q, t, d, mid))
				ll = mid;
			else
				lr = mid;
		}
		int rl = -1;
		int rr = N;
		while(rl+1 < rr) {
			int mid = (rl+rr)/2;
			if(exceedRight(N, ss, Q, t, d, mid))
				rr = mid;
			else
				rl = mid;
		}
		
		System.out.println(rr-lr);
		sc.close();
	}
	
	static boolean exceedLeft(int N, int[] s, int Q, int[] t, int[] d, int p) {
		for(int i=0; i<Q; i++) {
			if(s[p] == t[i]) {
				if(d[i]==1) {
					if(p==N-1)
						return false;
					p++;
				} else {
					if(p==0)
						return true;
					p--;
				}
			}
		}
		
		return false;
	}
	static boolean exceedRight(int N, int[] s, int Q, int[] t, int[] d, int p) {
		for(int i=0; i<Q; i++) {
			if(s[p] == t[i]) {
				if(d[i]==1) {
					if(p==N-1)
						return true;
					p++;
				} else {
					if(p==0)
						return false;
					p--;
				}
			}
		}
		
		return false;
	}
}
