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>
typedef long long ll;

int main(void) {
  ll i, j, k, n, q, a = -1, b;
  scanf("%lld%lld", &n, &q);
  b = n;
  char s[n + 10], t[q][3], d[q][3];
  scanf("%s", s);
  for(i = 0; i < q; ++i) scanf("%s%s", t[i], d[i]);
  for(i = q - 1; i >= 0; --i) {
    if(d[i][0] == 'L') {
      if(t[i][0] == s[a + 1]) a++;
      if(t[i][0] == s[b]) b++;
    } else {
      if(a != -1 && t[i][0] == s[a]) a--;
      if(t[i][0] == s[b - 1]) b--;
    }
    if(b - a == 1) break;
  }
  printf("%lld", b - a - 1);
  return 0;
}