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
N,Q=map(int, input().split())
s=input()
S=len(s)
A=[]
for i in range(Q):
  x,y=input().split()
  A.append((x,y))
  
if N==1:
  for x,y in A:
    if s[0]==x:
      print(0)
      exit()
  print(1)
  exit()
  
def L(d):
  for x,y in A:
    if s[d]==x and y=='L':
      d-=1    
    if s[d]==x and y=='R':
      d+=1
    if d<0:
      return False
    elif d==S:
      d-=1
  return True

ok,ng=S,-1
mid=(ok+ng)//2
while abs(ok-ng)>1:
  mid=(ok+ng)//2
  if L(mid):
    ok=mid
  else:
    ng=mid
p=ok
if ok==S:
  print(0)
  exit()

def R(d):
  for x,y in A:
    if s[d]==x and y=='L':
      d-=1    
    if s[d]==x and y=='R':
      d+=1
    if d>=S:
      return False
    elif d<0:
      d+=1
  return True

ok,ng=-1,S
mid=(ok+ng)//2
while abs(ok-ng)>1:
  mid=(ok+ng)//2
  if R(mid):
    ok=mid
  else:
    ng=mid
q=ok

print(q-p+1)
