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>
using namespace std;
#define MOD 1000000007
 
int main() {
  int N,Q;
  cin >> N >> Q;
  string s;
  cin >> s;
  vector<string> t(Q);
  vector<string> d(Q);
  for(int i=0;i<Q;i++){
    cin >> t[i] >> d[i];
  }
  
  int pos_l=0;
  int pos_r=N-1;
  for(int i=Q-1;i>=0;i--){
    if(d[i]=="R"){
      if(pos_l-1>=0){
        if(s[pos_l-1]==t[i][0])
          pos_l--;
      }
      if(s[pos_r]==t[i][0])
        pos_r--;
    }else{
      if(pos_r+1<N){
        if(s[pos_r+1]==t[i][0])
          pos_r++;
      }
      if(s[pos_l]==t[i][0])
        pos_l++;
    }
  }
  
  
  cout<<pos_r-pos_l+1<<endl;
  return 0;
}