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
I=sys.stdin.readlines()
N,Q=map(int,I[0].split())
S=I[1][:-1]
query=[]
for i in range(Q):
  query.append(list(I[i+2].split()))
  if query[i][1]=='L':
    query[i][1]=-1
  else:
    query[i][1]=1
L,R,M,X=0,N+1,0,0
while R>L:
  M=(L+R+1)//2
  if M==0:
    R=M
    break
  if M==N+1:
    L=M
    break
  X=M-1
  for i in range(Q):
    if query[i][0]==S[X]:
      X+=query[i][1]
    if X==-1 or X==N:
      break
  if X==-1:
    L=M
  else:
    R=min(M,R-1)
P=[1]*(N+2)
for i in range(R+1):
  P[i]=0
L,R=0,N+1
while R>L:
  M=(L+R)//2
  if M==0:
    R=M
    break
  if M==N+1:
    L=M
    break
  X=M-1
  for i in range(Q):
    if query[i][0]==S[X]:
      X+=query[i][1]
    if X==-1 or X==N:
      break
  if X==N:
    R=M
  else:
    L=max(L+1,M)
for i in range(R,N+2):
  P[i]=0
print(sum(P))