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 sys
n,q=map(int,input().split())
s=input()
l=[[i for i in l.split()] for l in sys.stdin]
def right_fallen(x):
  stack=x
  for i in range(q):
    if stack==n:
      return True
    if stack==-1:
      return False
    if l[i][0]==s[stack]:
      if l[i][1]=='R':
        stack+=1
      else:
        stack-=1
  if stack==n:
    return True
  return False
def left_fallen(x):
  stack=x
  for i in range(q):
    if stack==n:
      return False
    if stack==-1:
      return True
    if l[i][0]==s[stack]:
      if l[i][1]=='R':
        stack+=1
      else:
        stack-=1
  if stack==-1:
    return True
  return False
def binary_search():
  ok=n
  ng=-1
  while(abs(ok-ng)>1):
    mid=(ok+ng)//2
    if right_fallen(mid):
      ok=mid
    else:
      ng=mid
  return ok
def binary_search2():
  ok=-1
  ng=n
  while(abs(ok-ng)>1):
    mid=(ok+ng)//2
    if left_fallen(mid):
      ok=mid
    else:
      ng=mid
  return ok
print(binary_search()-binary_search2()-1)