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 <cstdio>
#include <iostream>
#include <string>

using namespace std;

char ts[300000], ds[300000];

int main() {
  int N, Q;
  string s;

  cin >> N >> Q >> s;

  for (int i = Q - 1; i >= 0; i--) {
    char t, d;
    scanf("\n%c %c", &t, &d);
    ts[i] = t; ds[i] = d;
  }

  s = " " + s + " ";
  int l = 1, r = N;

  for (int i = 0; i < Q; i++) {
    char t = ts[i], d = ds[i];
    if (d == 'L') {
      if (s[l] == t && l != 0) l++;
      if (s[r+1] == t && r != 0) r++;
    }
    else if (d == 'R') {
      if (s[r] == t && r != N + 1) r--;
      if (s[l-1] == t && l != N + 1) l--;
    }
  }

  cout << r - l + 1 << endl;
}

