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 <bits/stdc++.h>
#include <assert.h>

using namespace std;

int n, q;
string s;
vector<char> d, t;

int pos(int now)
{
  for (int i = 0; i < q; i++)
    if (s[now] == d[i])
    {
      if (t[i] == 'L')
        now--;
      else
        now++;
      if (now < 0)
        return -1;
      if (n <= now)
        return 1;
    }
  return 0;
}

int main()
{
  cin >> n >> q >> s;
  d.resize(q);
  t.resize(q);
  for (int i = 0; i < q; i++)
    cin >> d[i] >> t[i];
  int l, r;
  int ok = n, ng = -1;
  while (ok - ng > 1)
  {
    int mid = (ok + ng) / 2;
    if (pos(mid) == -1)
      ng = mid;
    else
      ok = mid;
  }
  l = ok;
  ok = -1, ng = n;
  while (ng - ok > 1)
  {
    int mid = (ok + ng) / 2;
    if (pos(mid) == 1)
      ng = mid;
    else
      ok = mid;
  }
  r = ok;
  cout << r - l + 1 << endl;

  return 0;
}