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
# -*- coding: utf-8 -*-
import sys

N,Q=map(int, sys.stdin.readline().split())
s=raw_input()
q=[ sys.stdin.readline().split()  for i in range(Q) ]

def leftout(cur):
	for x,y in q:
		if s[cur]==x:
			if y=="L":
				cur-=1
			elif y=="R":
				cur+=1
		if cur<0:
			return True
			break
		elif cur>N-1:
			return False
			break			

	else:
		return False


def rightout(cur):
	for x,y in q:
		if s[cur]==x:
			if y=="L":
				cur-=1
			elif y=="R":
				cur+=1
		if cur>N-1:
			return True
			break
		if cur<0:
			return False
			break
	else:
		return False


l=-1
r=N
while r-l!=1:
	m=(l+r)/2
	if leftout(m):
		l=m
	else:
		r=m
sl=l

l=-1
r=N
while r-l!=1:
	m=(l+r)/2
	if rightout(m):
		r=m
	else:
		l=m

sr=r


ans=N
if sl>=0:
	ans-=(sl+1)
if sr<N:
	ans-=(N-sr)

print ans
