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() + '#'
T = []
D = []
for t, d in [input().split() for _ in range(Q)]:
  T.append(t)
  D.append(-1 if d=='L' else 1)

#そのゴーレムがどちらかの端にたどりつけるかの関数
def canReachEnd(iL, dir):
  nowL = iL
  nowt = s[iL]
  for t, d in zip(T, D):
    if t == nowt:
      nowL += d
      nowt = s[nowL]
  if dir == 1 and nowL == N+1:
    return True
  elif dir == -1 and nowL == 0:
    return True
  else:
    return False

#1. iは左にたどり着くがi+1は辿りつかないようなiを探す
left = 0
right = N+1
while right > left+1:
  check = (left+right)//2
  if canReachEnd(check, -1):
    left = check
  else:
    right = check
leftborder = left

#2. jは右にたどり着くがj-1は辿りつかないようなjを探す
left = leftborder
right = N+1
while right > left+1:
  check = (left+right)//2
  if canReachEnd(check, 1):
    right = check
  else:
    left = check
rightborder = right

dropcnt = 0
dropcnt += leftborder
dropcnt += (N-(rightborder-1))
print(N-dropcnt)
