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=[input().split()for _ in range(q)]
def check(i,x):
  for t,d in td:
    if s[i]==t:
      if d=="L":i-=1
      else:i+=1
    if i==x:return True
    if i==-1 or i==n:return False
  return False
ok=-1
ng=n
while ok+1!=ng:
  mid=(ok+ng)//2
  if check(mid,-1):ok=mid
  else:ng=mid
ans=ng
ok=-1
ng=n
while ok+1!=ng:
  mid=(ok+ng)//2
  if check(mid,n):ng=mid
  else:ok=mid
ans+=(n-ng)
print(max(0,n-ans))