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<cstdio>
#include<cstdlib>
#include<algorithm>
#include<iostream>
#include<queue>
#include<vector>
using namespace std;
#define MAX 300000
typedef long long ll;

char t[MAX],d[MAX];
ll N,Q;
string s;




bool mycheck(ll goal,ll place){
  for(ll i=1;i<=Q;i++){
    if(t[i]==s[place-1]){
      if(d[i]=='L') place--;
      else place++;
    }
    if(place==goal) return true;
    if(place==0 || place==N+1) return false;
  }
  return false;
}

int main(){
  cin>>N>>Q>>s;

  for(ll i=1;i<=Q;i++){
    cin>>t[i]>>d[i];
  }

  ll s=0,e=N+1,ans0,ansN,ans,h;
  h=(s+e)/2;

  while(true){
    if(mycheck(0,h)) s=h;
    else e=h;
    h=(s+e)/2;
    if(s+1==e) break;
  }
  ans0=s;

  s=0,e=N+1;
  h=(s+e)/2;

  while(true){
    if(mycheck(N+1,h)) e=h;
    else s=h;
    h=(s+e)/2;
    if(s+1==e) break;
  }
  ansN=e;
  if(ans0+1>=ansN) ans=N;
  else ans=ans0+(N+1-ansN);
  cout<<N-ans<<endl;




}
