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
import sys
input = sys.stdin.readline
n,q = map(int,input().split())
s = input().rstrip()
td = [list(input().rstrip().split()) for i in range(q)]
def judge(x,direction):
  if direction == "L":
    if x == n:
      return True
    if x == -1:
      return False
    jpos = lambda w: True if w>=0 else False
  else:
    if x == -1:
      return True
    if x == n:
      return False
    jpos = lambda w: True if w<n else False
  for i in range(q):
    if td[i][0] == s[x]:
      if td[i][1] == "R":
        x += 1
      else:
        x -= 1
    if jpos(x) == False:
      return False
    if not 0<=x<n:
      return True
  return True
l = -1
r = n
while l+1<r:
  m = (l+r)//2
  if judge(m,"L"):
    r = m
  else:
    l = m
ansl = r
l = -1
r = n
while l+1<r:
  m = (l+r)//2
  if judge(m,"R"):
    l = m
  else:
    r = m
ansr = l
print(max(0,ansr-ansl+1))
