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()
q = []
for _ in range(Q):
  t,d = map(str,input().split())
  q.append([t,d])

def check(x):
  for t,d in q:
    if s[x] != t: continue
    if d == "L":
      x -= 1
    else:
      x += 1
    if x < 0: return -1
    if x >= N: return 1
  return 0

# checking left position
ok,ng = -1,N
while abs(ok-ng) > 1:
  x = (ok+ng)//2
  if check(x) == -1:
    ok = x
  else:
    ng = x
left = ok

ng,ok = -1,N
while abs(ok-ng) > 1:
  x = (ok+ng)//2
  if check(x) == 1:
    ok = x
  else:
    ng = x
right = ok

d = 0
if left != -1:
  d += left+1

if right != N:
  d += N - right

print(N-d)