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
def remain(pos,length):
  p=pos
  for c,d in moves:
    if s[p]==c:
      if d=='L':
        p-=1
      if d=='R':
        p+=1
    if p<0 or p>=length:
      return False
  return True

n,q=map(int,input().split())
s=input()
moves=[list(map(str,input().split())) for _ in range(q)]
l=-1
r=n
while r-l!=1:
  mid=(l+r)//2
  if remain(mid,n)==True:
    r=mid
  else:
    l=mid
remain_left=r
if remain_left==n:
  print(0)
  exit()
l=remain_left
r=n
while r-l!=1:
  mid=(l+r)//2
  if remain(mid,n)==True:
    l=mid
  else:
    r=mid
remain_right=l
print(remain_right-remain_left+1)