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 = "0"+input()+"0"
info = [input().split() for i in range(q)]

def solve(pos):
  for i in range(q):
    if s[pos] == info[i][0]:
      if info[i][1] == "L":
        pos = pos - 1
      else:
        pos = pos + 1
    if pos == 0:
      return True
    elif pos == n+1:
      return False
  return False

def solve2(pos):
  for i in range(q):
    if s[pos] == info[i][0]:
      if info[i][1] == "R":
        pos = pos - 1
      else:
        pos = pos + 1
    if pos == 0:
      return True
    elif pos == n+1:
      return False
  return False
ans = n
ng = n+2
ok = 0
while abs(ng - ok) > 1:
  mid = (ng+ok)//2
  if solve(mid):
    ok = mid
  else:
    ng = mid

ans = ans - ok

s = s[::-1]

ng = n+2
ok = 0
while abs(ng - ok) > 1:
  mid = (ng+ok)//2
  if solve2(mid):
    ok = mid
  else:
    ng = mid

ans = ans - ok

print(ans)
