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() + "#"
TD = [list(input().split()) for _ in range(q)]
TD = [(t, -1) if d == "L" else (t, 1) for t, d in TD]

def test(i, end):
  color = s[i]
  for t, d in TD:
    if t == color:
      i += d
      if i == end:
        return True
      color = s[i]
  else:
    return False
  
# 左に落ちるゴーレムの数(left)を探す
ng = n + 1
ok = 0
while abs(ok - ng) > 1:
  m = (ok + ng) // 2
  if test(m, 0):
    ok = m
  else:
    ng = m
left = ok

# 右に落ちるゴーレムの数(right)を探す
ng = 0
ok = n + 1
while abs(ok - ng) > 1:
  m = (ok + ng) // 2
  if test(m, n + 1):
    ok = m
  else:
    ng = m
right = ok

ans = right - left - 1
print(ans)