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) throws Exception {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int q = sc.nextInt();
		String s = sc.next();
		String[] t = new String[q];
		String[] d = new String[q];
		for (int i = 0; i < q; i++) {
			t[i] = sc.next();
			d[i] = sc.next();
		}
		sc.close();

		int left = binarySearchLeft(s, t, d);
		int right = binarySearchRight(s, t, d);
		System.out.println(right - left - 1);
	}

	static int binarySearchLeft(String s, String[] t, String[] d) {
		int start = -1;
		int end = s.length();

		while (Math.abs(end - start) > 1) {
			int mid = (end + start) / 2;
			if (isDeadLeft(s, mid, t, d)) {
				start = mid;
			} else {
				end = mid;
			}
		}
		return start;
	}

	static int binarySearchRight(String s, String[] t, String[] d) {
		int start = -1;
		int end = s.length();

		while (Math.abs(end - start) > 1) {
			int mid = (end + start) / 2;
			if (isDeadRight(s, mid, t, d)) {
				end = mid;
			} else {
				start = mid;
			}
		}
		return end;
	}

	static boolean isDeadLeft(String s, int idx, String[] t, String[] d) {
		for (int i = 0; i < t.length; i++) {
			if (t[i].equals(s.substring(idx, idx + 1))) {
				if ("L".equals(d[i])) {
					idx--;
				} else {
					idx++;
				}
			}
			if (idx < 0) {
				return true;
			}
			if (s.length() <= idx) {
				return false;
			}
		}
		return false;
	}

	static boolean isDeadRight(String s, int idx, String[] t, String[] d) {
		for (int i = 0; i < t.length; i++) {
			if (t[i].equals(s.substring(idx, idx + 1))) {
				if ("L".equals(d[i])) {
					idx--;
				} else {
					idx++;
				}
			}
			if (idx < 0) {
				return false;
			}
			if (s.length() <= idx) {
				return true;
			}
		}
		return false;
	}
}
