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>
#define fi first
#define se second
using namespace std;

long long n, q;
string s;
vector<pair<char, char>> v;

long long solve();

int main() {
  cin >> n >> q;
  cin >> s;
  v.resize(q);
  for(int i = 0; i < q; ++i)
    cin >> v[q - 1 - i].fi >> v[q - 1 - i].se;
  cout << solve() << endl;
  return 0;
}

long long solve() {
  long long l = 0, r = n - 1;
  for(int i = 0; i < q; ++i) {
    if(l < n && v[i].fi == s[l] && v[i].se == 'L') ++l;
    if(r >= 0 && v[i].fi == s[r] && v[i].se == 'R') --r;
    if(l > 0 && s[l - 1] == v[i].fi && v[i].se == 'R') --l;
    if(r < n - 1 && s[r + 1] == v[i].fi && v[i].se == 'L')
      ++r;
  }
  return max(0LL, r - l + 1);
}