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 <iostream>
#include <string>
#include <vector>
using namespace std;

struct Command {
  char t, d;
};
int main() {
  int n, q;
  cin >> n >> q;
  string s;
  cin >> s;
  vector<Command> commands;
  for (int i = 0; i < q; ++i) {
    char t, d;
    cin >> t >> d;
    commands.push_back((Command){t, d});
  }
  auto f = [&](int c) { 
    int cur = c;
    for (int i = 0; i < q; ++i) {
      if (commands[i].t != s[cur]) continue;
      if (commands[i].d == 'L') --cur;
      else ++cur;
      if (cur >= n || cur < 0) return cur;
    }
    return cur;
  };
  int l = -1, r = n;
  while (r-l>1) {
    int c = (l+r)/2;
    int nc = f(c);
    if (nc >= 0) r = c; else l = c;
  }
  // cerr << l << " " << r << endl;
  int min = l;
  l = -1, r = n;
  while (r-l>1) {
    int c = (l+r)/2;
    int nc = f(c);
    if (nc < n) l = c; else r = c;
  }
  int max = l;
  cout << max-min << endl;
}

