output_description: Print the answer.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N Q
      s
      t_1 d_1
      \vdots
      t_{Q} d_Q
attempt: n,q=map(int,input().split())
  s=list(input())
  s1=[1 for i in range(n)]
  for i in range(q):
    t[i],d[i]=input().split()
  for i in range(q):#回数
    if d[i]=="R":
      for j in range(n)[::-1]:#マス番号
        if t[i]==s[j]:
          if j==n:
            s[j]=0
          else:
            s[j+1]=s[j+1]+s[j]
    if d[i]=="L":
      for j in range(n):
        if t[i]==s[j]:
          if t[i]==s[j]:
          if j==0:
            s[j]=0
          else:
            s[j-1]=s[j-1]+s[j]
  count=0
  for i in range(n):
    count=count+s[i]
  print(count)
problem_description: Statement
  
  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.
samples: [{"input": "3 4\n    ABC\n    A L\n    B L\n    B R\n    A R", "output": "2\n    \n\n  * Initially, there is one golem on each square.\n  * In the first spell, the golem on Square 1 tries to move left and disappears.\n  * In the second spell, the golem on Square 2 moves left.\n  * In the third spell, no golem moves.\n  * In the fourth spell, the golem on Square 1 moves right.\n  * After the four spells are cast, there is one golem on Square 2 and one golem on Square 3, for a total of two golems remaining.\n\n* * *"}, {"input": "8 3\n    AABCBDBA\n    A L\n    B R\n    A R", "output": "5\n    \n\n  * After the three spells are cast, there is one golem on Square 2, two golems on Square 4 and two golems on Square 6, for a total of five golems remaining.\n  * Note that a single spell may move multiple golems.\n\n* * *"}, {"input": "10 15\n    SNCZWRCEWB\n    B R\n    R R\n    E R\n    W R\n    Z L\n    S R\n    Q L\n    W L\n    B R\n    C L\n    A L\n    N L\n    E R\n    Z L\n    S L", "output": "3"}]