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)]
def func0(x):
  # はじめx(0-indexed)にいるゴーレムが0から左にいき消滅するか
  for t,d in td:
    if t==s[x]:
      if d=='R':x+=1
      if d=='L':x-=1
    if x<0:return True
    if x>n-1:return False
  return False
def funcN(x):
  # はじめx(0-indexed)にいるゴーレムがn-1から右にいき消滅するか
  for t,d in td:
    if t==s[x]:
      if d=='R':x+=1
      if d=='L':x-=1
    if x<0:return False
    if x>n-1:return True
  return False

l,r=-1,n
while r-l>1:
  x=(l+r)//2
  if func0(x):
    l,r=x,r
  else:
    l,r=l,x
a=l
l,r=-1,n
while r-l>1:
  x=(l+r)//2
  if funcN(x):
    l,r=l,x
  else:
    l,r=x,r
b=r
print(n-(a+1)-(n-b))