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
def main():
	n, q = map(int, input().split())
	s = "."+input()+"."
	pm = [input().split() for _ in range(q)]

	def is_outside(x:int) -> int:
		for point, move in pm:
			if s[x] == point:
				if move == "L":
					x -= 1
				else:
					x += 1
			if x == 0:
				return -1
			if x == n+1:
				return 1
		return 0

	ok, ng = 0, n+1
	while ng - ok > 1:
		mid = (ng + ok) >> 1
		if is_outside(mid) == -1:
			ok = mid
		else:
			ng = mid
	l = ok

	ng, ok = 0, n+1
	while ok - ng > 1:
		mid = (ng + ok) >> 1
		if is_outside(mid) == 1:
			ok = mid
		else:
			ng = mid
	r = ng

	print(max(r-l, 0))

if __name__ == '__main__':
    main()