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, S, *L = open(0).read().split()
N = int(N)
Q = int(Q)
l = -1
r = N
while l+1<r:
  s = (l+r)//2
  p = S[s]
  m = s
  for t,d in zip(*[iter(L)]*2):
    if p==t:
      if d=='L':
        m -= 1
      else:
        m += 1
    if m<=-1:
      l = s
      break
    if N<=m:
      r = s
      break
    p = S[m]
  else:
    r = s
ans = l+1
l = -1
r = N
while l+1<r:
  s = (l+r)//2
  p = S[s]
  m = s
  for t,d in zip(*[iter(L)]*2):
    if p==t:
      if d=='L':
        m -= 1
      else:
        m += 1
    if N<=m:
      r = s
      break
    if m<=-1:
      l = s
      break
    p = S[m]
  else:
    l = s

ans += N-r
print(N-ans)