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 <algorithm>
#include <utility>
#include <vector>
using namespace std;
 
int N, Q;
 
int falldir(int i, string &str, vector<pair<char,char>> &spells){
  for(auto s : spells){
    char t = s.first; char d = s.second;
    if(t==str[i]){
      // hit
      i += (d=='L'?-1:1);
      if(i<0){ return -1; }
      else if(i>=N){ return 1; }
    }
  }
  return 0;
}
 
int main(){
  cin>>N>>Q;
  string s;
  cin>>s;
  
  vector<pair<char,char>> spells;
  
  for(int h=1;h<=Q;h++){
    char t,d; cin>>t>>d;
    spells.push_back(make_pair(t,d));
  }
  
  int l=0, u=N;
  while(u-l>1){
    int m = (u+l)/2;
    if(falldir(m,s,spells)<0) l=m;
    else u=m;
  }
  int lower = l;
  
  l=0; u=N;
  while(u-l>1){
    int m = (u+l)/2;
    if(falldir(m,s,spells)>0) u = m;
    else l=m;
  }
  int upper = u;
  int ans = upper-lower-1;
  
  cout<<max(ans,0)<<endl;
}