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;

int main(){
  int N,Q;
  cin>>N>>Q;
  string s;
  cin>>s;
  vector<char> j(Q);
  vector<char> LR(Q);
  vector<bool> ans1(N,false);
  vector<bool> ans2(N,false);
  for(int i=0;i<Q;i++){
    cin>>j[i]>>LR[i];
  }
  char mL=s[0],mR=s[N-1];
  int lp=0,rp=N-1;
  for(int i=Q-1;i>=0;i--){
    if(LR[i]=='L'){
      if(lp<N&&lp>=0&&j[i]==s[lp]){
        if(lp<N) ans1[lp]=true;
        lp++;
      }
      if(rp<N-1&&rp>=0&&j[i]==s[rp+1]){
        if(rp<N) ans2[rp+1]=false;
        rp++;
      }
    }
    if(LR[i]=='R'){
      if(rp<N&&rp>=0&&j[i]==s[rp]){
        if(rp>-1) ans2[rp]=true;
        rp--;
      }
      if(lp<N&&lp>0&&j[i]==s[lp-1]){
        if(lp>-1) ans1[lp-1]=false;
        lp--;
      }
    }
  }
  int cnt=0;
  for(int i=0;i<N;i++){
    if(ans1[i]||ans2[i])
      cnt++;
  }
  cout<<N-cnt<<endl;
}
