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

bool check(int i, string& s, vector<char>&t, vector<char>&d, int c){
  for(int j=0; j<t.size(); j++){
    if(s[i]==t[j]){
      if(d[j]=='R')i++;
      else i--;
    }
  }
  return i==c;
}

int main(){
  int n, q;
  cin >> n >> q;
  string s;
  cin >> s;
  s.insert(s.begin(), '#');
  vector<char>t(q), d(q);
  s.push_back('#');
  for(int i=0; i<q; i++)cin >> t[i] >> d[i];
  int ok1=0, ng1=n+1;
  while(ng1-ok1>1){
    int mid=(ok1+ng1)/2;
    if(check(mid, s, t, d, 0)){
      ok1=mid;
    }
    else {
      ng1=mid;
    }
  }
  int ok2=n+1, ng2=0;
  while(ok2-ng2>1){
    int mid=(ok2+ng2)/2;
    if(check(mid, s, t, d, n+1)){
      ok2=mid;
    }
    else {
      ng2=mid;
    }
  }
  cout << ng2-ok1;
  cerr << ok1 << endl;
  cerr << ng1 << endl;
  cerr << ng2 << endl;
  cerr << ok2 << endl;
  return 0;
}
