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() + ' '

ps = [0, N+1]
dirs = { 'L': -1, 'R': 1 }
QS = [input().split() for _ in range(Q)]
def drop(p):
  for t, d in QS:
    if S[p] == t:
      p = p + dirs[d]
      if p == 0 or p == N+1:
        return 1 if p == N+1 else -1
  return 0

# 二分探索
f = 0
t = N+1
while f + 1 < t:
  mid = f + (t-f)//2
  ret = drop(mid)
  if ret != -1:
    t = mid
  else:
    f = mid
p1 = f

f = 0
t = N+1
while f + 1 < t:
  mid = f + (t-f)//2
  ret = drop(mid)
  if ret == 1:
    t = mid
  else:
    f = mid
p2 = f
print(max(0, p2-p1))