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
#include <stdio.h>

int main(){
  int n, q;
  scanf("%d%d", &n, &q);
  char s[200001];
  scanf("%s", s);
  char t[200001], d[200001];
  for(int i=0; i<q; i++){
    scanf(" %c %c", &t[i], &d[i]);
  }

  /* 改良 */
  int count=0;
  int count2=0;
  int r=n-1;

  /* 呪文の実行 */
  for(int i=q-1;i>=0;i--){
    if(d[i] == 'R'){
      if (s[count-1] == t[i]) {
        count--;
      }
      if(s[r] == t[i]){
        r--;
      }
    }else if(d[i] == 'L'){
      if(s[r+1] == t[i]) {
        r++;
      }
      if(s[count] == t[i]) {
        count++;
      }
    }
  }

  if(r < 1){
    count2 = 0;
  }else{
    count2 = r-count+1;
  }

  printf("%d\n",count2);
  return 0;
}
