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 bichk(x,flg):
  if not 0<=x<n:return False
  now=[x,s[x]]
  for t,d in td:
    if t==now[1]:
      if d=='L':
        x-=1
        if x<0 and flg:return False
        if x<0 and not flg:return True
        now=[x,s[x]]
      else:
        x+=1
        if x>n-1 and not flg:return False
        if x>n-1 and flg:return True
        now=[x,s[x]]
  return True
l,r=0,n
# 左から落ちないゴーレムの最小座標
while r-l>1:
  x=(l+r)//2
  if bichk(x,True):
    l,r=l,x
  else:
    l,r=x,r
l0=l if bichk(l,True) else r

l,r=0,n
# 右から落ちないゴーレムの最大座標
while r-l>1:
  x=(l+r)//2
  if bichk(x,False):
    l,r=x,r
  else:
    l,r=l,x
r0=r if bichk(r,False) else l
if l0==n-1:print(0)
elif r0==0:print(0)
else:
  print(max(0,r0-l0+1))
